Ten experts (CEOs, professors) of each of the fields of math, physics, chemistry, economics, engineering, electrical engineering, CS, sociology, psychology, art, politics and education (120 total) are sent back in time to recreate the 21st century in a different timeline.

They can carry as many books and notes as they want but nothing electrical (fries the time machine).

They use solar eclipses and parlor tricks to be accepted as leaders of a German tribe unconditionally. The clan has 10,000 members.

Let's assume conflict between the professors and tribe members is not a factor and they all speak the same language.

The experts are ageless but are sent back after 100 years.

How far into the future can they push the tribe, or whoever else they conquer, in that time frame? Will more time make a difference?

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    $\begingroup$ There were no Germans 10000 years ago, so you must mean a tribe of people living in what is now Germany. (I didn't notice the date, specified only in the title, and wanted to suggest that they move south to the Mediterranean to learn from the civilizations there.) $\endgroup$ Commented Oct 16, 2019 at 15:36
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    $\begingroup$ worldbuilding.stackexchange.com/questions/54976/… $\endgroup$
    – Karl
    Commented Oct 16, 2019 at 19:55
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    $\begingroup$ Are they allowed to carry seeds, (domestic animal) sperm [with some means to keep it viable for years], baby (or even adult) animals etc.? It would be a lot easier - and more rewarding - to kickstart farming or herding with fully domesticated species, than to try to domesticate appropriate species in only 100 years. $\endgroup$ Commented Oct 17, 2019 at 0:31
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    $\begingroup$ And finally, I agree with others - this would be easier if I could pick the fields in which the 100 prophets are expert, and also have less duplication. I want a blacksmith more than I want a psychologist, and certainly more than I want the 10th psychologist. I'd rather have a person with experience farming, or at least gardening, than the 10th physicist. $\endgroup$ Commented Oct 17, 2019 at 0:38
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    $\begingroup$ Also, nothing electrical. What's electrical? copper? doped silicon? solder? microfilm? $\endgroup$
    – tuskiomi
    Commented Oct 28, 2019 at 5:03

32 Answers 32


Not a full 21st century world, but we can get close to it in some ways.

10,000 members tribe in post-glaciation Germany would be HUGE, but let's take it for a fact. One of the problems is that 10,000, even 20,000 people is not even close to enough to accomplish our task. And German lands are not fertile enough to support big preindustrial population.

Here is a possible strategy for the team. Let me stress that this is not a likely outcome but rather a strategy that has a non-zero chance to be successful.

Phase I (5-10 years)

  1. Establish a position of unquestionable authority in the tribe. Establish a suitable religion (Christianity should be Ok), and people should treat the experts like prophets sent by God;
  2. Organize the entire tribe in military fashion. Every member should devote his or her time to training and "godly" tasks;
  3. Teach everyone common language (spoken by all experts, so, English?), common-sense rules like sanitation and military tactics;
  4. Identify more talented tribe members and start training them as scientists and engineers. Regular people would be learning only necessary subjects like common language and the trade they going to be engaged in in the next 5-10 years;
  5. Get agriculture going. Experts must be able to bring with them seeds of plant cultures which were non-existent in 10000 BP, otherwise, the plan would fail;
  6. Get iron bloomeries going. Mass produce simple items like spearheads and arrowheads;
  7. March entire tribe to the Southeast. With the obtained level of training and armament, it should be able to defeat any opponent and conquer any land;
  8. As the march progresses, pick up new members who will be converting to the tribe's religion. Train them in common language and basic skills;
  9. Eventually, conquer already populated fertile areas along the Mediterranean coast.

Phase I goal accomplished - the tribe resettled itself in a fertile area and, counting conquered tribes, should grow its numbers to 50,000 members or more. All original tribe members should already be fluent in common language, with new members are quickly learning it.

Phase II (25-30 years)

  1. The experts should have new cultures' (like corn and potatoes) seeds with them. Now is the time to prepare big fields and start large scale planting;
  2. Build a city with necessary infrastructure which can support a larger city (roads, water supply, basic sewer) and social institutions (church, police, fire brigade etc);
  3. Wage occasional war to conquer neighbors, but mostly grow by welcoming new people via offering them security and food supply;
  4. Identify nearby mineral deposits, start mining;
  5. Set up large scale ironworks, chemical industry, and textile production;
  6. Build ships to travel all around the Mediterranean;
  7. Continue training more scientists and engineers. The new generation should be similar in aptitude to modern students. At least 10% of the population by the end of this phase should be "learned" class having what we call "professional occupation";

Phase II goal accomplished - tribe established itself as an antique style city-state with a total population over 200,000, well-supplied with food. Tech available: concrete, spinning wheel, steel, basic fertilizers, 1700s era ploughs. Metalworking and chemical engineering should already allow for the construction of firearms, although this should not be necessary at this phase.

Phase III (25-30 years)

  1. Build firearms and set up new colonies. Use conquest if more expedient;
  2. In new colonies, repeat the process that was successful in the first city;
  3. Start an industrial revolution. Build steam engines and factories;
  4. When steel would become cheap and abundant, proceed with railroads and steamboats;
  5. Extract oil and set up refineries (although Mediterranean basin is poor in oil, so gasoline-powered vehicles would be largely skipped in this scenario);
  6. Set up production of magnet wire and other supply items for electrical components.

Phase III goal accomplished - the tribe has turned into a Mediterranean empire with well over 1,000,000 total population. Tech available: steam engine, gas turbine, electric motor, radio, rubber, explosives, telescope, and microscope.

Phase IV (25-30 years)

  1. Build electric plants and power supply lines;
  2. Convert factories and railroads to electric power;
  3. Build industry for making of electronic components;
  4. Build industry for plastics production;

Phase IV goal accomplished - a microchip-based computer is built, a practical electric car is produced, a nuclear weapon can be built, if desired.

So, in 100 years we aren't quite getting to 21 century, but we are close. A key to this scenario is quickly building a large population and educating it while trying to avoid extensive wars and epidemics. The above timeline is very aggressive and failure at any step can derail the entire process, but at least in theory it can be executed.

P.S. It would be better if expert teams can be rotated. For example, 10 nuclear physicists would be essentially useless in the first 80 years, but they may be indispensable in the last 10.

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    $\begingroup$ no way would you get microchips in that timespan and with that technology. Remember that even in the real 20th century, with industrialisation already complete, we started with vacuum tubes. $\endgroup$
    – Tom
    Commented Oct 18, 2019 at 12:56
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    $\begingroup$ Reality check: I know a 1000 people factory whose sole purpose is to build valves to be used in components which filter the air in computer chip factories. This does not take into account the engineers designing them and all the supporting industry building materials good enough for them. The whole world population at the time won't even be able to make an industrial revolution with steam engines. $\endgroup$
    – Sam
    Commented Oct 18, 2019 at 13:31
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    $\begingroup$ @Sam I agree, though Steams a bit pessimistic as the requirements to make steam engines we met pretty much in the bronze age. en.wikipedia.org/wiki/Aeolipile $\endgroup$
    – pjp
    Commented Oct 18, 2019 at 14:20
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    $\begingroup$ It looks like phases 2-4 all have 25-30yrs listed on them. Is this a typo? $\endgroup$
    – scohe001
    Commented Oct 18, 2019 at 14:21
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    $\begingroup$ It's not entirely clear that the whole of the Mediterranean region had a million people to conquer at that point in history. The most pessimistic estimates for the total global population at that point aren't much higher. And if you are conquering areas by force, you have to assume that some people are getting killed in all the wars of conquest. The number of people working towards the goal in this scenario seems wildly optimistic. $\endgroup$
    – wrosecrans
    Commented Oct 18, 2019 at 21:37

You can't get anywhere close to that technology level. The best you could do is work to increase their life expectancy. Teach them farming. Teach them how to get water from a river into their fields. Teach them about cleanliness and basic first aid medical care.

If your group of people can boost the life expectancy long enough to actually have grandparents. Then you reach a very high productivity time where children learn from their elders, while the fit people are out working the fields and creating food. Once all the basic needs are taken care of, the population will grow, and the intelligence will grow with it.

The old saying is very true, give a man a fish, he eats for a day, teach him to fish, he eats for a lifetime.

A bonus would be if you can invent a religion that supports the growth of science and technology without destroying the Earth.

If you can modify your situation slightly to be able to bring animals like sheep, chickens and cows, that would help a lot.

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    $\begingroup$ Comments are not for extended discussion; this conversation has been moved to chat. $\endgroup$
    – Tim B
    Commented Oct 18, 2019 at 10:02
  • $\begingroup$ You can't get anywhere near to that technology level globally [+], I agree, unless they bring a great deal of equipment & tech with them to start with just getting to that technology level in one small geographically discrete nation or city state in just 100 years might be a stretch, & you have to get that done b4 you can spread it 'globally', $\endgroup$
    – Pelinore
    Commented Oct 26, 2019 at 13:50


But I'm answering this from a different perspective: world population.

10,000 years ago, the world population was around 10-20 million. And this population was spread across the globe.

Your experts would only find small villages, consisting on average of several hundred people at most.

Even if your experts could convince everyone to do exactly as they instructed, such little manpower would not enable the 21st century to be recreated in only 100 years. It just can't be done.

Recreating the 21st century would still take thousands of years or longer, even with the growth of technology caused by your experts. This is due to the lack of human resources needed to create the technologies at the rate needed to do so.

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    $\begingroup$ What if you recreated gunpowder, and metallurgy, to produce automatic weapons? You could field a vastly superior army, with knowledge of modern warfare tactics. Inslave your enemies and you have enough manpower to do pretty much whatever. $\endgroup$
    – Innovine
    Commented Oct 16, 2019 at 10:53
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    $\begingroup$ @Innovine after building chemical plants, mines, factories, etc. plus infrastructure to get your workers concentrated near those facilities, acricultural improvements to feed all those people,..... $\endgroup$
    – ths
    Commented Oct 16, 2019 at 11:19
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    $\begingroup$ @Innovine It seems reasonable only because there are thousands of years worth of developments you're taking for granted. Agriculture itself only became a suitable replacement for gathering after hundreds of years of selecting crops to increase their caloric benefits-- it's pretty hard to speed that process up with stone age technology. Also, aside the fact that those 32,000,000 people are spread across the whole globe with no way of gathering in the same spot, there's the important fact that pretty much all of them need to spend their energy on subsistence activities... $\endgroup$ Commented Oct 16, 2019 at 23:07
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    $\begingroup$ (cont) lest they all starve to death in the winter. The further back you go in human history, the less a society could afford to have people sitting around working on things unnecessary for survival, like mines or perfecting a new smelting technique. You could offset this a little by being able to orient them down the most efficient technological path and teaching them basic hygiene techniques, but it'll still take a super long time to even reach medieval technology. $\endgroup$ Commented Oct 16, 2019 at 23:15
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    $\begingroup$ @Innovine if the slaves get these easy to use weapons, you'll have the age old "my gun's bigger than yours" contest. In other words, where there are weapons, people die. $\endgroup$ Commented Oct 17, 2019 at 10:12

Let's manage our expectations a little, and consider a fairly discrete (but certainly iconic) 21st century technology: firearms. But let's manage expectations further and try to create a modern firearm's 14th-century ancestor: the cannon.

A cannon is, crudely, a lump of metal with a big hole at one end and a tiny hole at the other, into which you pour gunpowder, wadding and a roughly-spherical shot; then you point the big hole at the enemy and put fire into the small hole.

These sound like simple requirements, but a 8000BCE Germanic tribe is only able to deliver you the last two: they controlled fire, and they'd be able to weave you something to use as wadding. Gunpowder and the cannon barrel are your main challenges.

To make gunpowder you need saltpetre, sulfur and charcoal.

Charcoal wasn't yet invented, but its production technique is not difficult and you could set up a charcoal kiln with stone-age tools. Make sure one of your time travellers understands how to make and run a charcoal kiln (maybe this could be a job for one of the CEOs :p). They'll probably be managing several hundred people in the charcoal production pipeline, most of whom will actually be woodcutters (felling trees with stone axes is hard work, and since the only domesticated animal at this time is the goat, moving them manually is even harder). In fact, since that's a really fundamental requirement, set another one of the CEOs the task of teaching the domestication of animals. In 5-10 years the productivity of this foundation level of civilisation will shoot up.

Saltpetre is potassium nitrate, which can be mined from caves inhabited by certain types of bat, or (more practically) manufactured in pits filled with manure, urine and straw. Sounds like you'll definitely need those domesticated animals then, and this sounds like exactly the sort of enterprise that is calling out for a CEO's talents. Most of the workers they'll be leading here will be keeping the pits moist with urine (they take a year each to fully decompose) and then leaching the output with water (you could maybe build a watermill to assist with some of the heavy lifting here, finally a job for an engineer). This method requires potash to convert the calcium nitrate to potassium nitrate, though, so you'll need a separate industry for that.

Potash is usually shaft-mined, and here you encounter all the same problem as you'll find trying to mine iron ore for the cannon barrel (which we haven't even started on yet): building a whole mining infrastructure with stone-age tools. Frankly, building and maintaining a single deep mine with all its supporting industries could occupy your entire tribe; I'm actually going to handwave over this part.

Sulfur, fortunately, is abundant at the surface and can be easily collected by hand, although it would again be back-breaking work. You'll need to crush and grind it to a powder and do your best to remove impurities.

Let's take stock. You've employed probably over a thousand of your tribesmen and half a dozen of your time travellers, building up industries that will produce raw materials that might allow you to create a raw material that forms one of the simplest components of an invention that's a thousand years simpler than your target timeframe. These industries will take a couple of years to get up to speed before they are producing the raw materials that could be used to start building up their dependent industries.

It would be astonishing how much progress, relatively speaking, the time travellers could achieve in a century. But it would be equally remarkable how far they still had to go.

One good thing does come out of all this, though: your cohort of CEOs would have plenty of valuable jobs to do...

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    $\begingroup$ I really had overlooked how much work goes into materials. I thought they were just always available in some capacity since 10000 years doesn't seam THAT long ago. But yeah my plan seams to fall apart at the seams. At least the germans now have a fun way to blow up each others straw huts $\endgroup$ Commented Oct 15, 2019 at 17:14
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    $\begingroup$ Except that straw is a byproduct of cereal farming, which was only just kicking off in the Levant, so you'd need to start that first :-p $\endgroup$
    – Stephen
    Commented Oct 15, 2019 at 17:21
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    $\begingroup$ @user2741831, 10000 years ago really is that long. It's the mid-Neolithic, and the height of technology in Germany is carefully-worked stone tools. You'd be better off in the Near East, where you could add farming to the list of technologies, or China, where you get pottery. $\endgroup$
    – Mark
    Commented Oct 16, 2019 at 1:33
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    $\begingroup$ Don't forget your "arts" and economics professors. They could help your CEOS..... $\endgroup$
    – Thorne
    Commented Oct 16, 2019 at 2:03
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    $\begingroup$ You do not have a very good trade network, so sourcing materials and chemicals from far away is a major blocker, regardless of your tribes tech level, they cannot trade for something the other tribes don't know how to produce. You'd need to spread industry and knowledge of chemistry just to source rarer elements. $\endgroup$
    – Innovine
    Commented Oct 16, 2019 at 10:57

No, As it is you will be lucky to have any impact at all.

You have a lot of dead weight and you are missing the most important fields.

Things your forgot

  1. The first thing you need is better food production, for that you need biologists, agricultural scientists and soil scientists. without them, most of your effort is wasted and you may do more harm than good. The society may not be able to support your experts without better food production. Food ALWAYS comes first, people need to be fed before you worry about anything your experts can do. 10,000 years ago in Germany they would have neither plows nor oxen to pull them, so you need to domesticate animals (or travel across Europe) to even start improving farms.

  2. the second thing you need is geologists, that lets you get raw materials for fertilizer, metals, chemistry, and good old drinking water. Before the advent of geology finding minerals was down to luck and your chemists are going to be hamstrung. Also I assume chemists included metallurgists, if not that is a huge oversight.

  3. Also you need medical experts, improving standard of living fast is the best way to ensure they both want what you are giving them and can actually put it into practice. Without them the first plague could wipe out all your work. More importantly you need people who understand nutrition, picking the wrong crops will put your hosts in worse position then before you got there.

And why for the love of all that is beautiful would you not send a few historians or anthropologists, people who might actually be able to predict coming events and problems before they occur.

Dead weight

  1. As for dead weight criminal science* and art will be basically useless in the setting, criminal science doesn't have any of the tools or infrastructure needed to have any impact, especially if you already have politicians, nor do they really bring anything unique to the table. * If CS means computer science, then you want a few of them but not ten, they will spend the vast majority of the time being useless.

  2. Your hosts will have artists so your not gaining anything by bringing more.

  3. You don't need both 10 political experts and 10 economists, if your political experts don't understand economics they weren't worth bringing along.

  4. Mathematics will be useful but not enough that you need 10 mathematicians, you can probably half that number or more the applications will see a lot of cross compatibility with your engineers. Your electrical engineers are just dead weight for a good long time, especially without the aforementioned experts needed to actually start advancing technology.

How to fix it.

Drop artists and all or most of your CS, and at least half your economists and psychological scientists as well as half your mathematicians. Replace them with agricultural scientists, geologists, medical experts, and anthropologists/historians. You can drop a few electrical engineers and political scientists to make up the difference. If you have some room to squeeze a few full fledged biologists in, even better.

Honestly, you could probably drop a lot of the late game applications down to 1-2 individuals per field, physics is going to be largely covered by engineering, by the time tech advances enough for actual physicists to come into play you should be training up a whole batch of native scientists. Ditto for computer science and to a lesser extent psychology. Even 10 educators may be overkill since educators can teach up new educators relatively quickly (compared to some of the other skills) and and most of your experts should be cross trained in education, so your late game experts should be acting as educators for a good long while.

Ideally you could drop a few experts and fill their seat with expertly chosen seeds. Maybe even a few oxen. You'll get more bang for your buck if you rely mostly on books for some of the more non-interpretive sciences and start with a huge boost in agricultural output and infrastructure.

Even then 100 years is unattainable, too much of modern technology relies on a huge population of specialists, you just can't get the numbers fast enough. You need millions of trained specialized people to support modern technology.

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    $\begingroup$ I suspect CS means computer, rather than criminal, science. $\endgroup$
    – Zwuwdz
    Commented Oct 16, 2019 at 4:10
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    $\begingroup$ @Zwuwdz Though, still as useless. As someone who did Comp Sci at university, there is absolutely nothing a computer scientist can contribute at this point that the mathematicians and EEs can't. $\endgroup$
    – tylisirn
    Commented Oct 16, 2019 at 5:45
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    $\begingroup$ I agree the selection of experts is poor. If this was lifted to sending whatever experts you like, how would you change your answer? $\endgroup$
    – Innovine
    Commented Oct 16, 2019 at 11:00
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    $\begingroup$ @tylisirn I actually think EE+CS would be more practical than EE+Mathematics. As someone who studied EE with a CS minor, I'd say the EE's should be able to handle practical continuous math with real and imaginary values well enough (up to stuff like diffeq/linear algebra), and the CS guys should be able to handle whatever discrete math is necessary. If they hit the point where they need math that a CS or EE expert can't handle, they've probably beat the prompt already (I don't think they will). $\endgroup$
    – Zwuwdz
    Commented Oct 16, 2019 at 17:48
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    $\begingroup$ Also remember to scout so you don't get cannon rushed or 6 pooled. $\endgroup$
    – Vaelus
    Commented Oct 17, 2019 at 11:56


I think other answers do a pretty good job of covering most of the issues. I would just like to add a few points:

  1. The biggest bottleneck to the advance of civilization is the available energy
  2. The biggest bottleneck to a fast-forward of civilization is domestication

Major advances in human history usually occur when humans learn to harness a new energy source, whether it's fire (from wood, peat, animal dung), water (dams, water wheels), animals (draft horses, cows, etc.), fossil fuel (coal, oil), steam, nuclear, etc.


Food/agriculture is, of course, the most essential energy source, as it is necessary to maintain the most important machine in your plan: the humans. However, despite the popularity of slavery over much of early human history, humans are not actually the best draft animals. They have fairly picky food requirements compared to herbivores, they mature slowly, and they are on the weaker side when it comes to muscle density/power-to-weight. Your enterprise will go much faster if you can herd and harness draft animals.

But first, just think about something simple like your basic cheeseburger. You also want cattle because they give you high-quality protein and fat via beef and milk. This alone solves a good chunk of your food problem. Growing a cow is roughly equivalent to feeding several humans on wild pastures. Given the primitive state of technology, you need every bootstrapping advantage you can get.

Draft Power

You should be able to build crude windmills and water wheels even with stone age technology. This will give you some decent energy with a modest investment of time and effort. Of course, you need the relevant wind and water resources nearby, but you can always relocate your budding civilization to favorable locations. It should also be very feasible to build low, basic dams in 100 years on at least small to medium size rivers. This should give you pretty significant draft power near such rivers.

Unfortunately, a windmill is not very useful for plowing fields, which you need to be doing pretty heavily to start up agriculture. You need mobile power. You need draft animals. And this is where things get tricky. While human plow teams can certainly do the job inefficiently, they aren't going to do it nearly as well as oxen that you can feed on wild pastures/hay. And animals have not been domesticated 10 kya (except maybe cats, but I'd really love to see a plow team of cats!!!).


We don't know exactly how long it takes to domesticate an animals, but even the most optimistic estimates would be on the order of dozens of generations. It may have taken more than 1000 years to domesticate chickens. While you can cheat on the plant species by bringing seeds, as others have suggested, it is probably also highly desirable to bring a box of newly hatched chicks. A diverse population of baby pigs, cows and horses would also get you around the domestication trap, but now size is a considerable constraint.

Time Machine

You obviously wanted to limit the technology that the time travelers could bring with them, to see how far they could get on a "pure knowledge bootstrap". Well, seeds or chicks/calfs/lambs could be seen as "cheating" in this respect. If not, then you must also consider other "non-electrical" cheats, like a hammer and a saw. Obviously, bringing a few steel saws, a few smithing hammers, chisels, and other passive tools would be a massive help in making precision cuts for your mills, quarrying stone for dams/bridges/foundations/etc.

If you think about how labor intensive the production of a single stone hammer is, you can see that even if you are able to build a primitive bloomery, you'll still need a fair number of stone tools to make productive use of the crude iron you're able to produce. You can expect most useful, productive stone tools to take hundreds, if not thousands of hours to produce. Just getting out of the Stone Age is going to take a lot of back-breaking manual labor!

Population Growth

As many have noted, one of the biggest bottlenecks to industrialization is raw population size. A modern economy has thousands of niches which must be filled by large numbers of workers. 10k citizens may sound like a lot of people to you, but only because you live in a globalized society. You don't need all 7+ billion people to produce the computer that you wrote this question on, but you would be hard-pressed to do it with less than a million. You need mines all over the world to access productive sources of rare earth elements, and so at some point you will need a truly global population.

While you probably don't need the entire Isle of Britain to launch an industrial revolution, it should be instructive to note that in the 1800s, the UK had a population between 10 and 15 million citizens. I would be very impressed if you could repeat that feat with 10% of their population.

Now, Seallussus did some math on population, and I will finish the math. If we define a 15-year generation, then you can fit 6 generations in 90 years. With a 10x growth rate per generation, you get a $10^6$, or 1 million x population growth in less than a century! That's pretty good, but it requires each woman to average 20 children, which is about 1 child per year for 20 years, from 15-35. If women continue to bear children until menopause, you get some wiggle room for infant mortality, occasional infertility, accidental premature deaths, etc.

Frankly, I think that an average of 20 children per woman is pushing the limits of human capability. Although a woman is attested to have birthed a whopping 69 children (no, that's not a joke), the fact that the list includes women who had "merely" 20 children suggests that this is pretty unusual. Modern societies have a high of 6-7 children per woman (c.f. Niger). Thus, I find 10 children per woman to be near the edge of believability, especially for an entire civilization. This only gives you a 5x multiplier, and $5^6 = 15,625$. Fortunately, that still gives you a population of 15+ million citizens, which, as we saw above, is right about the population of Britain during the Industrial Revolution. The 1,000,000 x multiplier would give a population of 10 billion, which isn't plausible unless you really nailed every single technology in perfect synchrony and spread across the globe in 100 years.

Note that if a woman has 10 children, the next generation will have 10x the people, but only half of them will be females (on average), so this only results in a long-term growth of 5x. But, each generation will actually have 2x the predicted population because of all those useless, non-birthing males sitting around watching football and demanding beer. So you could lower the birth rate even more to 8 children per woman, for a 4x generation multiplier, or $4^6 = 4,096$x total multiplier, giving a final generation population of about 8.2 million citizens. This is well within the realm of plausible birth rates, and still gives you a very useful population size.


Although most other answers mention war, I think your story would be much more awesome if your civilization simply awed would-be competitors with their awesomeness, and everyone wanted to join under peaceful conditions. It would also save significant resources if they didn't have to divert time and materials to swords, armor, and guns. Remember, you not only have a technology race on your hands, but a population race. The rest of the world is not going to be enjoying your 8x technology-driven population boom, so any armed conflict is going to be a hit to your population growth/target.

Traveler Demographics

Totally agree with the answers which value CEOs near the bottom of the ladder of usefulness. You want agricultural scientists, geologists, metallurgists, chemists, doctors (both to treat the existing population and to teach), but 1 thing more than all the rest: teachers!

You see, trying to teach adult stone age humans English (or any other language) is going to be a constant uphill battle. Teaching children, on the other hand, shouldn't be that much more difficult than teaching children today. After all, we mostly carry around cave man brains to school. So, consider the first generation on arrival as your least-useful bootstrappers. They can do grunt work via mime and direct apprenticeship, but probably not worth it to try teaching them to read and inspect blueprints.


On the other hand, you need the women to pump out babies like they are going out of style, and you want every one of those kids to have a 21st century education, to the extent you can make that possible. Assuming your population has mostly uniform ages from 0-60, you will have 1,000 children (about 10% of the population) aged 6-12. If you bring 50 teachers, you can maintain a student:teacher ratio of 20:1. Not ideal, but pretty typical for a modern day classroom. But wait! That's not enough! You don't want to quit with just an elementary education! You want to give them at least 12 years of instruction, which will require 2x the teachers to maintain the class size...that's 100 teachers! But now you have a problem...the next generation is going to be 4x the size, and you can't bring 400 teachers. You need to train teachers, and to do that well, you need more than 12 years of instruction. You need closer to 18 years. So you probably need to increase class sizes to 30:1, because not only do you need 300 new teachers from this generation, you will want scientists, mathematicians, engineers, biochemists, and everything else as well!

So, you have 3,000 citizens in the range 6-24, and 100 teachers each teaching a class of 30 students, which I'd say is on the edge of practicality. And 20 folks left over to bootstrap iron-making, geological exploration, sanitation, agriculture, and everything else you need. I can tell you right now that none of them need to be (or ought to be) CEOs, artists, or philosophers.

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    $\begingroup$ About milk: Did the tribes at that time already evolve the gene to digest milk as adults? I doubt it, as before milk was generally available through domesticated animals, it didn't provide an evolutionary advantage. And If those tribes couldn't drink milk, you'll face trouble with your milk-based nutrition plan. $\endgroup$
    – celtschk
    Commented Oct 16, 2019 at 7:28
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    $\begingroup$ Also, your population growth figures don't take into account illnesses. Especially since you didn't consider health issues at all, expect most of those children not to reach adulthood. With 10 children per woman, you'll be nowhere close to 5x population growth per generation. $\endgroup$
    – celtschk
    Commented Oct 16, 2019 at 7:36
  • $\begingroup$ Minor correction: Domestication of sheep, goats and cattle was done 10,000 years ago - but, in the Near East (Afghanistan/Iran/Turkey/etc), and would not reach Germany for another 1000 years or so $\endgroup$ Commented Oct 16, 2019 at 8:23
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    $\begingroup$ I like the idea that you are better off replacing some of your expert humans with domesticated animals. $\endgroup$ Commented Oct 17, 2019 at 3:09
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    $\begingroup$ @celtschk And it should be noted much of the infant death in the past has been related to starvation (either directly or through allowing disease to spread much more readily). How do you feed that 5x growth of population? How do you clothe them, train them, etc.? Even if you could get every family to have ten kids, where do you get the capital to support them? $\endgroup$
    – Luaan
    Commented Oct 18, 2019 at 8:41

Will they be able to recreate the 21st century? No, not even close

They could definitely bring major advancements and insights (better weaponry, cleanliness and basic healthcare, etc) which would make that tribe one of the greatest in it's time. Maybe they could get to the first industrial revolution, but definitely not the second. It wouldn't change as much as you think.

Most modern advancements require complex machining and manufacturing processes which themselves require different metals and resources: that is, resources that require collaboration from many societies around the earth.

One of the key things is trade and collaboration. In ancient times you might get a few tribes working together, but some other tribe may be incredibly violent (heck, the Vikings showed up out of nowhere during the Reconquista and caused problems for both the Christians and Muslims in Spain). Our modern advancements rely on large amounts of trade between states and countries. Most of the food we eat is not natural to where we are; we move food around from everywhere else. Those farms grow large amounts of that food because we give them resources they want.

No amount of knowledge or insight into technology will make people suddenly all participate in major national trade like that. Worse, when someone gets ahead, another tribe will try to kill everyone and steal it because back then they could get away with it.

Without the ability to bring resources through time with you, you're limited by what's available.

  • $\begingroup$ I would say the first industrial revolution is pretty close to the 21 century. I wasn't even sure they would make it that far. But what kind of things and how many of them would you bring along to make the task easier? $\endgroup$ Commented Oct 15, 2019 at 16:41
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    $\begingroup$ @user2741831 large amounts of weapons, machines, and millions of people. As far as first industrial revolution is pretty close .... it sounds like you're thinking about history as a linear progression upward. I would strongly disagree with that sentiment. Some technology has been lost to time, some has been recovered. There's a back-and-forth, and it's only the past 300/400 years that have seen the largest "jumps". $\endgroup$
    – cegfault
    Commented Oct 15, 2019 at 16:44
  • $\begingroup$ I honestly assumed with key inventions like electricity, steam engine, writing, ships and the light bulb the transition to the 21 century would happen on its own with other smart people filling in the gaps pretty much automaticly $\endgroup$ Commented Oct 15, 2019 at 16:53
  • $\begingroup$ You're not going to get the first industrial revolution. There's just too much really fundamental stuff missing (writing, arithmetic -- heck, even a mechanistic view of the universe is missing). Remember: the starting point is mid-Neolithic Germany. The development of pottery is still 2500 years in the future. Farming won't arrive from the Near East for another 3500 years. There may be some hammered copper or gold floating around, but smelting won't be discovered for another milleneum. The Bronze Age is still 5000+ years away. $\endgroup$
    – Mark
    Commented Oct 16, 2019 at 1:15
  • $\begingroup$ @Mark I agree it's a stretch, but if there were enough experts and they all agreed unanimously on everything and the society blindly accepted them as leaders/gods and they could raise 3-4 generations in a row (~100yrs) with their education (reading, writing, etc) and the society was isolated well enough from enemies and there were no droughts or famines, then maybe we could see some better farming tools, such as this patent for a basic churning device $\endgroup$
    – cegfault
    Commented Oct 16, 2019 at 12:23


There is way more knowledge between 8000BC and now than you could possibly stuff into any 120 people, no matter how smart they are. And they won't be around long enough to spread everything that they know to others.

Just for reference, a child today goes to school for ~12 years, followed by 4 years of university education, followed by maybe some 4+ years of graduate education. This is what it takes to educate one person with all of the advantages of 21st century technology, in a city packed with educated people, computers, and the like. 120 people couldn't even form a decent-sized university.

Also, if you want to invent things, you're going to need materials. Digging metals out of the ground, chopping down trees, making cement all takes time. And it will be extremely slow and inefficient if you're trying to get a Stone Age tribe to do it while teaching them at the same time. Even if you knew how to make all these awesome things, it would take forever to get the materials for you to even begin building physical prototypes.

  • 1
    $\begingroup$ Thats why I included the exemption for no conflict. $\endgroup$ Commented Oct 15, 2019 at 16:32
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    $\begingroup$ Kids today have more school than the average life expectancy back then. $\endgroup$
    – Trevor
    Commented Oct 15, 2019 at 16:32
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    $\begingroup$ Of course, they can do something. But the topic asks if they can get to the 21st century. The answer is no way. $\endgroup$
    – Priska
    Commented Oct 15, 2019 at 16:35
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    $\begingroup$ @user2741831 For gunpowder to be much use they need iron. Just getting to the point of having iron good enough to make gun barrels would take up much of that century. $\endgroup$
    – Zeiss Ikon
    Commented Oct 15, 2019 at 16:35
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    $\begingroup$ @Trevor - if you're old enough to go to school then we can take those who died before adolescence out of the equation, bringing the 'average' up to 50~60y, which was the average life span of a surviving adult. +30% child mortality rate is why we hear that number so much. $\endgroup$
    – Mazura
    Commented Oct 17, 2019 at 22:21

Before these people in the past can focus on absorbing all the new information your professors have they must first satisfy their own needs.

The ancient folk don't have time to sit around and listen to these professors, they have a proven way of life that demands large amounts of time tending crops and animals and producing their daily tools. As such I would expect most of the professors' time to be spent enhancing the existing farming and tool making techniques rather than introducing radical new changes that would threaten to have too large an overhead for the ancient people to maintain without causing mass starvation.

The most you could expect in 100 years is that the ancient folk have some basic hygiene knowledge and slightly better farming, I wouldn't even expect that the experts have a chance to develop new tools or production.

  • 1
    $\begingroup$ The target location is Germany, which is still solidly a hunter-gatherer society, with few domesticated animals (dogs, and perhaps sheep or goats). Farming is still thousands of years in the future. $\endgroup$
    – Mark
    Commented Oct 16, 2019 at 1:37
  • $\begingroup$ No one in the 21st Century even knows the languages the people from that time would speak. $\endgroup$
    – Dronz
    Commented Oct 18, 2019 at 3:16
  • $\begingroup$ @Dronz Once we have a time machine, that will no longer be the case. I can promise that! $\endgroup$
    – jpaugh
    Commented Oct 18, 2019 at 16:13
  • $\begingroup$ @jpaugh I didn't notice that possibility mentioned in the question's assumptions. Since the mentioned technology can't sent electrical equipment, how would time-traveling linguists get back to the future to help prepare this expedition? Maybe jumping forward isn't even possible? If it were possible to go back to learn the languages and cultures and situation in the past and then return to continue planning, it seems like a different scenario to me. $\endgroup$
    – Dronz
    Commented Oct 18, 2019 at 16:31
  • $\begingroup$ @Dronz I agree that time travel does not imply bi-directional travel; but the question did mention them (possibly) returning to their own time at the end of 100 years: "The experts are ageless but are sent back [to their own time] after 100 years." $\endgroup$
    – jpaugh
    Commented Oct 18, 2019 at 16:33

Some more expertises that you will need:

  • hand-to-hand combat. Multiplies your ability to resist invasions. Or "pacify" neighbors for extra labor force. Teach self-defense to your other experts.
  • mineralogist/geologist. Where are you going to place the mines for each different material? Already mentioned by @John You also need a map of natural resources, as mentioned by @Seallussus . Unless you like scouting millions of Hectareas of wild forest & mountain.
  • oven maker. you need to build mud/brick ovens powered by wood. Different specs for bread making, pottery making, smelting, cooking.
  • metallurgists/armorers. The judges of that TV contest where they manufacture different types of swords.
  • medics/nurses. If one of the other experts gets a bad cut, they might bleed to death or die from infection/gangrene.
  • survival specialist. Teach other experts how not to get lost/killed in the forest.
  • forrester. Germany has, like, a lot of trees. How are going to use all that wood? Deforestation, rotation of fields, which trees to cut, easier ways to cut/transport/etc. How do I produce vegetable carbon in safe and efficient way?
  • carpenter. What types of wood are needed for each manufacturing?
  • artisan. How do you manufacture skin & paper from scratch? What processes are already known to succeed/fail? People from medieval recreation fairs might have a lot of knowledge that you need and is hard to find from books.
  • weaver. One specialized on medieval or survivalist.
  • cook. Teach new recipes, exploit foodstuffs that are currently not used due to tradition/ignorance.
  • fisherman. modern tactics for nets & hooks. Practical knowledge, ability to show by doing.
  • builder/architect. You don't want your experts to live in old wooden huts prone to infestations of bugs, right? Or asphyxiated because their new chimney was badly-designed. People wil appreciate if can you build them bigger/better/warmer houses.

Other materials:

  • yeast: needed for yoghurt & bread (also cheese?). There are different types with different results. Different yeasts with different treatments, will give widely different results: arab bread, mother mass bread, etc. What about penicillin?
  • diamond tips: can write on any stone, lasts a very long time
  • $\begingroup$ Definitely +1 for the geologist! Especially if they can mine, smelt and have some smithing skills (I can name quite a few people with these skillsets in real life). If they can bring back paper geological surveys, I would think you have a pretty good chance to get to early 20th century at least $\endgroup$
    – Riddles
    Commented Oct 16, 2019 at 13:28
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    $\begingroup$ survival specialist? Any indigenous people are survival specialists in their own environment $\endgroup$
    – jean
    Commented Oct 16, 2019 at 20:30

No. The experts are experts on a specific society, the late industrial western civilization. In the past they won't have the infrastructure that their expertise relies upon.

Example: Metals. Even if they know where the ores are they need people to dig the ore, then refine it without the refining tools we have and then forge the metal without the forging tools we have. They won't be using armed concrete, for example, for a long time. They have to build EVERYTHING.

They may set examples and pass teachings in very useful areas like sanitation and optics (to create glasses and extend the productive lifespan of the ancient wisemen) but that's it.

Another thing is the persistent idea in other answers that if the experts create a religion to fool/guide the primitive barbarians and make the experts' books the holy scripture then everything will work out. That's very wrong, based in a late industrial western vision of what is religion, derived from the marxist idea that religions are ideologies (false sciences created to acquire and mantain power). Things were different in the ancient world and the people looked for certain signs of divine/magical/demonic action, like the discussions in Jamblicus' book, On The Mysteries. Your experts won't fool the ancient wisemen if they try to pull the "create religion" stunt and will end up executed for blasphemy. So the best course of action is to cooperate with the wisemen, try to pass knowledge that has immediate utility, like the sanitation, optics, pasteurization and, should the region where the experts appeared have advanced iron age metallurgy, electricity/radio.

You will never recreate 21th century tech but will empower the region with less mortality from diseases (sanitation/pasteurization), more productive wisemen(glasses), better communications(telescopes and telegraphs). In time this region will have a population boom and will be able to support it's own technological development, following it's own path.

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    $\begingroup$ I've never heard the term armed concrete before. Is it a calque from another language? Is it perhaps reinforced concrete (with iron bars through it) or pre-stressed concrete (the iron bars were under stress when the concrete was poured)? $\endgroup$ Commented Oct 17, 2019 at 9:54
  • $\begingroup$ @PeterTaylor, yes, you are correct, it's reinforced concrete, with iron bars inside. In my language is "concreto armado" and i didn't remember the correct english words $\endgroup$
    – Geronimo
    Commented Oct 17, 2019 at 12:23
  • $\begingroup$ Another thing i thought, rereading my question: Chlorine in water. Ancient alchemists were able to separate chlorine and sulphur from ores. Treating the water will save thousands from death by dysentery. $\endgroup$
    – Geronimo
    Commented Oct 17, 2019 at 12:27
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    $\begingroup$ Boiling water is lower tech and effective. Chlorine probably only becomes worthwhile when you're dealing with cities which are too large to rely on wells and rainwater. Once you're piping water in, you're most of the way to the infrastructure to treat it in bulk. $\endgroup$ Commented Oct 17, 2019 at 12:38
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    $\begingroup$ Knowing that germs exist (and how to control them) is probably going to save more lives than either Chlorine or boiling water on its own. $\endgroup$
    – jpaugh
    Commented Oct 18, 2019 at 16:12

Maybe, but as others have pointed out, your focus is wrong.

If they can bring back non-tech items other than books, then I think this might be possible.

If they could bring back modern strains of crops (corn, barley, oats, potato, apple, oranges, etc...) and modern farm animals (chickens, cows, pigs, horses, oxen, and sheep mostly) this would go a LONG way toward establishing a stable food supply for the native population.

I would say with the above resources (and the knowledge of modern fertilization/crop rotation), you could set up a retively modern food supply in 5-10 years.

The next order of buisness would be educating the native population, basics at first, have them become accustom to the animals, and the new farming techniques. while adults are learning and working then the real work of teaching the children to read would begin. Im not sure how far you would get with the first generation which is why you would start the education as quickly as possible and plan on the children of the children you first taught being the ones who can start doing real work/learning. I would expect to be able to reliably have the 2nd generation reading around year(s) 20-25.

Once you have a stable food supply and the beginnings of an educated population, the real work, and therefore the real progress, can begin.

You can then introduce fire, the wheel, the waterwheel, metalurgy, optics, the compass, paper, books, the printing press, electricity, the steam engine, the telephone, vaccination, refridgeration, air travel, penicillin, fission, semiconductors, computers, the internet, space travel...

Once the native population can read and educate themselves, they will just need the books (hence the printing press) to keep going. So after a few more generations of the native population go by, you should be nearly at the 100 year mark for the experiment, and if they're not up to "21st century level", then they would be in the next few generations.


It would make much more sense to send back people with useful skills related to survival and building than a lot of academics with nothing to offer. What are you expecting art professors to do in 10,000 BC? Or an electrical engineer in a place with no metal? What useful skills does a politics professor have outside of academia? (There's a reason that's the only place you find them).

I image your party would be found out and die off fairly quickly.

Send back people with skills in smallholdings, animal husbandry, medicine, midwifery , public healthy, construction from scratch and a whole lot of military types and your tribe might thrive. Or ir might not. There is a lot of luck involved.


Here are some random notes on the initial bootstrapping; I don't have time on my lunch hour to think about the later steps.

Some of the stuff you could do in the first year is domesticate horses, make bridles and saddles, and good bows and arrows. With that you could pretty much sweep the Eurasian landmass. (Granted not your goal, but this is basically how Proto-Indo-European was spread from Iceland to the Pacific.) (I've heard though that all domestic horses on the planet trace back to a single grandfather horse, and he might have been uniquely domesticatable. So, I'm not sure if you could have domesticated any random horse you found.)

You could introduce writing pretty much day one. That'd jump you a good 80% of the way to the present day right there. Ditto sanitation (mentioned by others). I don't have a good feeling whether the language of 10k years ago was as productive as what we speak now. In other words would they need to have a modern language to start doing modern tasks, or would their old language have, say, enough prepositions to describe all the things you'd like them to do?

A tricky one: are the scientists sent back in time full of poo? If so they should take care to eat all the domesticated seeds before their trip, which should pass through the digestive tract intact. If not, though, then you have a HUGE challenge: having a division of labor allowing a lot of people to work on things besides food requires those working on the food to gather a huge number of calories, which I don't think is possible without modern grains which have had millennia of selective breeding. Sure, you can introduce farming, but what would they farm? Raspberries? If you don't have the grains, I think that ends your plans right there. Even with all the books in the world, I think most of your expert's time might be devoted to gathering calories. (I've also heard that in some places this might take as little as a couple hours a day.)

Pottery should also be bootstrapable year one, which would help you store food from times of plenty for times of scarcity, which would increase the number of people who could be dedicated to non-food pursuits. I think you could get bronze going quite quickly too.

Portable fire with flint would be a big benefit; I don't think that existed then.

To the extent you wanted to power things with hydrocarbons, I think the area around Baku had lakes of oil on the surface. You might want to head there to start your revolution.

  • $\begingroup$ One year to domesticate an animal? $\endgroup$
    – Dronz
    Commented Oct 18, 2019 at 3:18

I think there a couple of points that is not mentioned here. This is not much of a detailed plan, but rather just a couple of important points.

  • How ruthless are your group? Are they willing to use slavery? Are they willing to allow polygamy? Would they use diplomacy or war to gain lands?...etc.
  • We tend to think of a skilled laborer as an adult with years of knowledge and both theoretical and practical knowledge. Well. Get a 9 year old, teach him about your sophisticated metal working methods.
    Then tell me how long would it take him to understand them and become proficient. Not long I'd wager.

  • Aside from programming or genetic engineering or stuff like that. Most, if not all, of our knowledge is fairly simple once we know about it. Penicillin is not magic, Newtons laws are not magic...etc. So knowing that electricity exists or that you need to do this and that to make a rifle...etc makes it a matter of how do I produce those with the available tools

  • Similar to the points above. You can start your empires training at a young age. The younger disciples would learn from the age of 9-10 to the age of 15-16 That mean means that you have someone with the knowledge and resources of a medieval blacksmith at the age of 20. At 30 they can start making muskets.

  • Population growth. How long would it take to increase your population with your improved healthcare and food surpluses? Well. It takes about 13-16 year, or even less if we abandon our current standards, for a girl to become of child childbearing age. And with the previous statements about how serious your government are about population, then marriage is legally required and none can remain single, females at least, and none can abstain from having children. She then takes less than a year to bring a child to the world that would take about 15 years to turn into a master in their discipline. I'm no mathematician. So my numbers would be off. But here is an attempt. Assuming an average age of mere 55, seems a reasonable number with our improvements, and that a woman become childbearing at the age of 15. Now assuming she is required by law to have a child every 2 years. Then it's about 20 child in here 55 years. Tough but not impossible. So about 20 of every single female of the first generation. So assuming your basic population of 10000 and assuming a neat 50/50 split, then your very limited basic tribe can supply about 75000 child. Heck. Let's cut the 25000. So 50000? Now the first generation would be 25000 females? They take about 15 years to start the cycle again, right? Now there is even more. Because we already talked about aggressive expansion. So while your starting pool is limited, once you start conquering new lands you can start having millions of population in half a century. And again with much better healthcare you can actually keep people alive for longer and eliminate the dreaded fear of childbirth. So a combination of war, slavery and aggressive populating would get you staggering numbers in 50 years.

  • War fatalities. How many on the ancient battlefield died because of a silly disease or a wound? Too many. But your improved army has better healthcare and you can actually fully cure most of your soldiers. So not only would you have more soldiers but your recovery rates would be higher. So imagine a legate with 20 of continual war experience. Now imagine that the average officer in your army is something like 6-10 years of war experience on every country in the world.

  • Military expansion. Genghis Khan lived for 65 years, Alexander of Macedon a mere 33 years. Neither of them knew anything that you military commanders knew. Can you even imagine the state of absolute disarray that the world was in? Honestly. I'm willing to wager that you can conquer the entire old world in less that 50 years. The biggest problem about maintaining large empires is communications and at some point you would have railroads. That's just a game changer. The Roman roads sure as heck were. Trains would be magic. And the thing is once your legion, I'll assume it's the basic unit, of 5000 can travel from Germany to Persia it a week you can effectively rule the world.

  • Speaking of expansion. You have a map of natural resources right? And different maps of the proper climate of each crop, right? Well. What are you waiting for! Turn an entire country to a farm, another to mines, a third to oil fields...etc. And with such a solid ruling elite you won't run into trouble. An important point here is that you are willing simply conquer at least the Mediterranean world if not most of the ancient world. And you have thousand of slave, then thousand of well supplied workers using the latest farming or mining...etc techniques...etc.

  • The biggest issue here is the first stage. Producing decent amounts of medicine and food and tools is vital. Since I'm not an expert on any of those subject I can't give you a detailed plan. Though of the blacksmiths of Japan found a way to make good swords with the crappy metals they have. And the Romans made concrete that we can't find out how, or how the Egyptians found a way to build the pyramids. I'm sure with perseverance, and a lot of firepower, you can give the idea a try.

  • Science can be fast. How long did it take us to build a car? Now from the of making a car to the making of an airplane, how long? So my final point is this. Even if it takes you 50 years to start making the more advanced stuff. Once you have the infrastructure then it's a piece of cake.


One factor that's going to cripple your ability to recreate the modern era is your supply chain. The modern world enjoys a global economy. We trade goods and raw materials with other people from all corners of the globe. Your scenario injects a massive knowledge infusion into a small group, but the rest of the world is still the same as it was. Your uber-tribe will be able to do amazing things, but only if they're doable with the resources available in their immediate vicinity.

Example: electronic components use a wide variety of elements that aren't easily obtained. For example, the primary source of gallium is bauxite, the ore used for producing aluminum. Your society won't have access to gallium until it can mine and refine aluminum (assuming it has bauxite it the first place). If you don't have it locally, you're now blocked waiting on the rest of the world to catch up with you. Even when you have the raw materials, the process of extracting and refining them is often times only economical at scale. With no external demand for refined materials, you likely won't be able to afford many basic industrial processes.


If you could take the resources available on the internet in book form--we're talking a LOT of paper--I think you would do pretty well.

The first trick is to have the current generation of people concentrate on resources for training the children and some simple first generation production (Farming, creating teaching tools, mining/mineral processing, housing, etc.). If you can train the children efficiently they should be on average MUCH smarter than the average person from today and you're off to a good start.

After 15-20 years of training the first generation of technical workers and working on the basics you should be ready to put together the next generation of tooling. After that it's just iterations and they will be comparatively fast.

You won't have the sheer numbers we have today--but very few of us actually push progress, we waste most of our energy sustaining our huge population. if everyone was working on the next generation thing constantly without waiting for "innovation", we'd have been moving at a much faster pace between the 000s and 1920, most of that progress could have probably been accomplished by a few thousand people in 20 years or so.

The biggest problem here is getting enough metal out of the ground and processed--mining has always been very manpower intensive and that hasn't really changed. I can only hope newer efficiencies and processes don't require as much.

The stuff from the end of the depression on has been at a faster pace, but we did it in 100 years, a well-trained thousand people with all the "Discoveries" pre-discovered should be able to do it much quicker, but this is where iterations can get tough (creating the machines you need to build the machines that can build the equipment you actually want).

I'm not sure the computer stuff could be sped up too much, you just need iterations. Perhaps this is where someone with the experience that Elon Musk has with his battery factory where innovation was "planed for" could make a huge difference.


They would have to write a book for the tribesmen, that would be copied on a printing press.

Having made tempered steel chisels and carved the most incredible stone carvings ever, you would essentially be the de-facto friendly alien from another planet. Together with knives, pots, pans, a saw-mill to make wooden planks, they wouldn't throw engraved illustrations of the technology on the floor and walk off.

10 professors armed with digital files could indeed reprint a vast library of knowledge, detailing most alloys, chemistries, physics, machines, political laws, biotechnology, medecine, used in the 21st century.

The development guide would have to include some transition technologies like ox ploughs and field medecine.

10 million pages would get them up to the 1970's / 1990's.

To get the tribe's interest and attention, the library would have to include maps of the world, statute books on world dominion, military defense / attack tools, carts, trucks, windmills, ox ploughs, wine presses, food processing, cranes, scaffolding, cements, architecture, and the library would be graded in steps of complexity. It would take at least 300 years for the tribal culture to adopt a scientific tradition.

Using the printing press and the library, they could come to parity with us in 700 years or something.

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    $\begingroup$ +1 for the printing press. It's hard to overstate its importance. $\endgroup$
    – krubo
    Commented Oct 16, 2019 at 9:55
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    $\begingroup$ -1 for the printing press. This is 8000s BC. The development of proto-writing (account markers and the like) is still two thousand years in the future; true writing won't evolve for at least another 2500 years after that. $\endgroup$
    – Mark
    Commented Oct 17, 2019 at 23:44
  • $\begingroup$ So you don't think that printing 4 wheel chariot schematics, the roman arch, the bread-mill, the illustrated ten-base counting system, the cog, the crane, the lever, 1+1=2, the animal pen, the dove-tail, would be a seminal element of development? Start by printing an illustrated dictionary, They will LOVE to learn to read it. people LOVE to learn to read. Whatever they can make with stone tools, should be illustrated on a printing press and distributed with latin titles. Did you want to wait 2500 years after the OP's 100 year deadline to give them a dictionary? $\endgroup$ Commented Oct 18, 2019 at 0:35
  • 1
    $\begingroup$ Start by printing an illustrated dictionary, and you'll be ignored. You're trying to give written materials to people who don't even have the background to understand the concept of writing, much less understand the writing itself. $\endgroup$
    – Mark
    Commented Oct 18, 2019 at 2:25
  • $\begingroup$ Actually, prehistoric people 10,000 years ago revered art-work. If you make some steel knives and a magic machine which can copy artwork, of a refinement beyond their wildest dreams, you will be able to communicate very well. They would have a list of metal objects to make on a printed page. Knives, wood saws, hammers, everything. Teachers use both a black-board and images and books to teach. Children are given coloring books with letters they don't understand, for a reason. writing will look like this: profilingtheunexplained.com/ufos_aliens/… $\endgroup$ Commented Oct 18, 2019 at 3:47

Since one progress made right after another is just not how human minds work, no, not in 100 years.

Instead of thinking in number-of-years think in generations. You can hyper progress one generation, lets say from hunter-gathering to farming but then you have to stop. Let dust settle. Make people see fruits of their efforts.

The next generation would make no progress at all. Thats how human minds work. The generation after that will be ready for progress, mostly after the first generation die off.

Look at advancement of physics in 20th century for example. Rapid progress between roughly 1890 to 1920, then nothing for long time, just stabilizing. Then starting roughly from 1970s some progress.

So, first progress, just move from hunter-gathering to farming, not push any more. Second progress, metal works. Third progress, firearms. Fourth progress, engines (rails, cars but not aircrafts). Fifth progress, aircrafts. Sixth progress, space technology till 1980s level.

Make progress in arts, culture, law etc go along these above progresses, in parallel, using non-science people.

Also make progress in computers along the way.

So, 12 generations, roughly 400 years; and thats when technology is handed over to those people, not developed by them.


In the 1632 series they have something of the same situation but 6 mile radius bit of USA moved from the year 2000 (or near it) and with it a town with all schools up to a high school, many small and some mid sized businesses, a power plant with enough staff to run it and so on.

They land in the middle of Germany (as is now) in an area with many people who are willing to join in and manage to get over the language problems (although German of the time misses a lot of words needed.)

With all those advantages over your scheme they do run into many bottle necks.

You need metal to build up an industrial base. To melt metal you need to build the basic metal industry (and your Germans will have non) and for that you need people who do not only know how to melt and refine metal in theory, you need people who know all from digging out the ore, the clay to make the smelters for each of the smelters and so on.

Your 120 high level specialists will likely not done any metal work with their own hands and even when they do have a hobby like primitive metals, they will likely only specialize in one kind of metal and not all.
And you will get that with all fields of tech, from textiles and food to the specialist fields like computers.

On top of that, (as shown in the 1632 series,) not all raw materials are available in Germany, some not even anywhere in Europe. Things like rubber, stainless steel, many food stuffs, ingredients for medications and so forth are not in Germany. And many medical supplies can not be made without a lot of 20th or 21st century equipment.

Also forget operations. And your specialists will bring germs the locals have not protection against, while your specialists may get ill from what is the norm for them.

I guess your specialists are way to specialized to even start the change and that they run a big risk of losing all because of disease or disaster they are not prepared for.

And that is assuming that they survive the initial meeting. If I found a group of strange people in my hunting grounds, I am not sure whether I would want to meet them or just kill them.


No. First you are sending back the wrong people, and secondly you are sending back too few of them. And finally, 21st century technology is dependent on 21st century population. It is utterly impossible without either more people than could be put under control in that timeframe or more advanced knowledge than we currently have...

Now, if you want 20th century tech, it’s another matter.

What you would need to do is basically send back a small 1830’s town, with enough farmers/ranchers/miners to keep them supported. Now, that sounds on the face of it like a huge increase in population, and it is, but probably not as much as you are thinking. Over a 1000 you’re getting near to being in the top 100 cities by population in the US at the time. Which means that a tenfold increase would put you in the ballpark, not too large and known to work.

With the increased population and the fact that you have made them all immortal apparently, you would be able to create a self supporting base that over the course of a hundred years would develop into a good size city with a low 20th century technology base.

Given that, it wouldn’t even be particularly hard. Given your immortals (or even just extended lifespan), then they could spend a few decades not only working out how best to develop the technologically progression from naked people to flying, but train your entire expeditionary force in the various skills they will need.

You’ll want farmers and bronc busters, miners and blacksmiths, carpenters and bowyers, potters and textile workers and as someone else pointed out, lots of teachers and midwives. Given the know-how (including experience, I would suggest 12 practice runs of the first month, 6 practice runs of the first year, and at least 1 practice runs of the first decade), it should be easy to develop what you absolutely need for low to mid 20th century tech over the course of a century —- the ability to feed and educate several hundred thousand people.

You don’t need to worry about going a-viking, most of the areas population is in groups of 50-200 people, and they will come to you if you have reliable food year round. In our history, the first known cities came about 4500 years after your target date, my suggested 1200 people immediately outnumber everyone else and while fight and raiding will be known, size should protect them. BTW, if you could drop maybe a dozen or two people a month or so in advance of your target, that would be really handy in making sure everything goes smoothly.

Once you’ve got your first city of 100,00 people with 1910 knowledge, you should be able to start spawning colonies around the globe without any real trouble, particularly if your immortals are still around. The colonies should be able to get started and grow much faster than the original — trade and the fact that they can start with tractors and such will allow them to draw in the required population quickly. In another hundred years it wouldn’t be surprising to have another 100 cities with populations in the hundreds of thousand. At that point you’re firmly in the 1930’s and up territory. Progress from there will depend upon local development and demand.


Even if all the materials are taken care of (if you can send a hundred people a few shipping containers should be doable) is simply measuring things reliably. A human can do centimetre-scale by eye or milimetre-scale with simple tools but if you want to get more precise (and for many modern engineering things like nuts and bolts you need a order of magnitude more) you need a micrometer and those came along in the 1700s. At their time they were a marvel only possible by using the latest and greatest technology.

Tell a modern engineer he'll have to build something without use of a micrometer and he'll just stare at you blankly.


In a hundred years, no. In two hundred, maybe but doubtful. Considering some of the caveats in other answers, I would say you’d need not only more time, but you’d have to find five or more villages friendly to each other and have some of your experts in each. You’d need a way to have messengers for the experts to communicate with each other. You’d have to go slowly enough to overcome the “indistinguishable from magic” problem. And you’d need to provide your benefits in sufficient quantities and low enough cost to keep other villages from obtaining them by force. (So you can concentrate on progress instead of on defense.) However, a limited threat is a good incentive to develop defense technologies.

If they’re all in only one village, there’s a greater chance of invasion ruining the project, while having the growth in more than one place improves the chance of it spreading. And covering a little more area increases your supply of food and materials.

If your goal is to accelerate the development of technology, maybe send some experts to that time, and some to later times to build on what the previous groups have done. And some really clever sales/propaganda people to get folks to honor/respect the experts instead of envy/resent them.

  • $\begingroup$ well look at that the CEOs are good for something afterall $\endgroup$ Commented Oct 16, 2019 at 16:29

Maybe, but you're going to need more than just 1 wave of experts.

So you want to create modern society, but 10,000 Before Present (B.P.) (or I guess 9,900 B.P. since you're giving them a century). Here's what you do: Send your experts back 11,000 B.P. to kick things off. Basic agriculture, hygiene, etc. Send another wave back to 10,900 B.P., to take advantage of the improvements brought on by the first group. Send another one to 10,800 B.P., 10,700, 10,600, etc. Each group should take the combined advances of all the previous groups and build upon them. (In fact you've said your group is ageless, so you could just use the same people each time.)

You might even send the group to multiple different locations within the same time period so you're not just advancing one specific group of humans but all of humanity across the globe. It's going to take a lot of work, and many separate trips to many locations, but if you're careful and patient, you could pull it off and have your modern society by 9,900 B.P., but only as the culmination of a millennium of guided improvements.


No as OP's setting.

10,000 years ago it's 8000 BC, people in the Eastern Mediterranean should already know some farming/agriculture, but for a German tribe? Probably NO. What is worse is in OP's setting there's no expert for agriculture... A hunter-gatherer tribe may not even have enough food to feed the experts, actually I doubt that any hunter-gatherer tribe could reach 10,000 population. Without agriculture, there's won't be enough food. Without enough food, there won't be enough "extra" people to work on mining/blacksmith/education/research/construction...basically everything "extra". So this plan probably won't work from the beginning.

If some adjustments can be made, like allow time travellers to bring some seeds/animals/basic tools, pick more experts from some fields like agriculture/medical/mining and metallurgy/...etc, my personal guess is they can reach tech level around 1800, or even 1900 in 100 years.

Source: History of agriculture

Size of hunter-gatherer tribe


It would definetly be possible

All you need is humans and 10000 members is quite a large number.

lets say, in worst case 1/3 are old people

1/3 are children, 1/3 are adults

lets take the adult women from the equation,

and you would have at least 1600 men to do the heavy work needed to start the industrial revolution.

Which is not bad.

The children would be able to get some good education, which would make everything easier in the following years.

As for the adult women, well, they would probably end up being full time mothers, as you would need to grow the population, to speed up everything.

So yea, they could.

Though food plays a huge factor in here, as the crops from back then would be quite bad, compared to the ones that we have today.

Even then I still believe they would be able to do it, even though the start would be quite slow, until the food issue would be solved.

And to answer your last question.

More time wouldn't make a difference(besides for them being there to steer them in the right direction in some cases, like some disease/war...), since all they would need to do there is to pass the knowledge to the tribe, which wouldn't take that long(maybe 30 years??)


A Resounding YES

As per the OP's question, we only need to replicate the 21st Century and populate it, we don't need to make the same mistakes, trial and errors, wars, dead end results or bad theories/misconceptions that normal development requires.

Many developments that constitute the modern structure of society have been developed in the last 100 years. Compared to 1919, 2019 has developed tremendously. Replicating the development within this period should be much easier considering knowledge already gained, and no need to make mistakes.

Many answers assume we need to slowly develop the Germanic tribe in the same way that it took 10,000 years to do so, however we only need to teach them what they need to know, which is what we know now. The rest is simply structure.

For instance, teaching a young child in the tribe as if he/she were modernly educated would achieve a good level of knowledge and education equivalent to today. The rest is environmental, with which the original 120 founders of society need to start work on.

So, in order to achieve this, we need to send back the following 120 people:

  • 20 Leaders: People who are expert at leadership, trained specifically in leading people, convincing them of cause, and good project management skills. Preferably they have degrees in political science and/or military officer training. These people will coordinate others in the group of 120. The reason we need 20 is that 1:8 is a good command ratio. This means each group of 10 experts needs 2 of these.

  • 50 Workers/Professionals: These are people who need to build the factories, mines, smelting and processing plants, to initially make materials than make machines capable of producing higher level products. Each discipline in the OP's question would have 4 of these.

  • 50 Teachers: These people need to educate the tribes people. With a group of 50, and a staff to student ratio of 1:30, you could teach 1500 students in the first generation. These would go on to teach a further 45,000 in the second, and more in the third. Their teachings would be the same level of knowledge as 21st century primary, secondary and tertiary teachings. Initial classes would be limited by scarce technology but as the Workers group, later assisted by educated tribesmen, start to produce results these can be transferred to education.

Again, it must be stressed that you don't need to develop everything up to 21st Century, you only need to replicate it as it is now, and train the native population to use it. Plus you have 100 years to smooth the society out.

With no conflict postulated as per the OP's question and the tribesmen already convinced to follow you, and 120 extremely smart experts in their fields, proportioned as above, you should be able to replicate, at least a smaller scale part of, the 21st Century.

  • 1
    $\begingroup$ Answers like this make me wish I had asked people to specify which team composition they would use $\endgroup$ Commented Oct 18, 2019 at 17:14

The answer is No, you cannot achieve 21st century civilization starting with nothing but 10,000 people in the Stone Age. The reason: you need population growth that can't be achieved in the Stone Age. Every answer you've received that has explained population growth has given you good information about how people die, except that they were generous when it came to mortality rates. None of the answers that I saw told you to bring an obstetrician as one of your specialists.

I've studied child and maternal mortality a little bit. Six to eight children per woman is about right if the husband is being considerate. But you all have forgotten that 1 out of 4 women die in labor without modern cleanliness and equipment. If we assume that the one woman is dying at the end of her child-bearing years, then she and the other 3 living women will have between them 24 to 32 births. If she dies at the beginning, then they will have 18 to 24 births.

That doesn't mean the children will grow up. 1 in 5 children died before the age of 5, and they died from things like dysentery, croup, cholera, teething (!), whooping cough, measles, fever, and meningitis. In some places, it was closer to 1 in 3 dying before the age of 5.

You can find on the internet something called a mortality schedule, sometimes called a morbidity table, that shows what people died of, how long they had been ill, what age and race they were, and lots of other factors. Genealogical sites have these. If you look one up from, say, 1850, you'll be shocked at how many die while still infants and toddlers.

Even "at the beginning of the 20th century, for every 1000 live births, six to nine women in the United States died of pregnancy-related complications, and approximately 100 infants died before age 1 year" (that's at the rate of 1 out of 10). This is from "Achievements in Public Health: 1900-1999" from the CDC.

So, in order to achieve the explosive population growth needed for 21st century technology, you have to improve not only cleanliness but also the general medical environment and equipment to 21st century standards. Sanitization isn't going to happen under Stone Age conditions.



The reasoning behind my YES is controversial, but even if you disagree with the reality of my hypothesis you can still use it as a plausible explanation in a work of fiction.

Firstly the ability to produce metals, wire, magnetise metals, and collect/produce chemicals, all with the purpose of generating and storing electricity, could plausibly be given to Neolithic tribes 10k years ago.

What this would give as a huge advantage to any one specific tribe is the ability to communicate at a distance, which would be an unsurpassable military advantage.

This would plausibly result in a social structure very different to Neolithic norms. It would also put the time travelers in a situation where their knowledge and ability to maintain the equipment would make them elites.

The problem is a lack of knowledge/understanding of mathematics and how a society could be shaped applied to engineering tasks, and how quickly electronics/computing could evolve.

My controversial solution to this is what I believe is the explanation behind the marvels of Egyptian calculation in pyramid building, or the accuracies of Maya astronomy. Namely, autism.

I think we have evolved not as individuals but as societies. Like beehives or anthills, humans are similar in the sense that societies have different roles and I hypothesise based on life experience that people are born with predispositions to these roles. As with wasps or bees, some are soldiers, some are queens. I think humans are born with predispositions to building, to driving (shepherding, riding), to farming and nurturing, etc.

I do not believe that autism spectrum represents an 'abnormality.' I would offer the conjecture that ancient Egyptians were excellent for their time at feats such as constructing pyramids because they had an inclusive society where those on the autism spectrum were recognized for their talents and conditions were such that they could feel comfortable and be productive.

Were Oracles, Seers, Prophets and Druids examples of how talented (and different) individuals were recognized in ancient times? Were the insights that Pythagoras brought merely descriptions of what the local human computers already knew intuitively, but unable to express?

In the end, reality is a subjective thing that is entirely created by the computer that is your brain. You and what you live in is all 'made of' consciousness that is generated post-hoc upon receipt of sensory stimuli in the external and objective reality, to which you have no access.

Everything is brain-generated. It is a computer.

So autism in my opinion is a deviation from the 'norm' in allocation of computing resources. The individual may lack coordination and social awareness, but in some cases can translate from multiple languages and self-teach advanced arithmetic as a child.

Could it not be the case that autism is a social evolution, a natural occurrence of a human computer so that basic mathematical and linguistic problems occurring daily in simple societies can be solved? A predisposition to certain abilities, for the benefit of the society, totally analogous to having a predisposition to singing/communicating, or a predisposition to strength and violence? Is it the case that autistic individuals are pushed into 'diagnostic categories' (aspergers etc) today merely because advances in computing and mathematics make them irrelevant, whereas before they were Oracles and Seers?

So with this view, I think the answer is YES, if a society can be shaped that empowers those types of individuals in an elitist structure, which would evolve quickly once the telecommunications advantages were brought through military dominance.

  • 1
    $\begingroup$ except they don't have the labor force to build any of this technology Also autism is not needed to learn math. Egypt was able to build so much because it was a heavily managed top down state, $\endgroup$
    – John
    Commented Oct 16, 2019 at 11:05
  • $\begingroup$ @John I think you are missing my point. My point was that a heavily managed elitist/well structured state would be necessary to have autistic members of society be given executive powers over a slave workforce. $\endgroup$
    – Sentinel
    Commented Oct 16, 2019 at 12:37
  • 2
    $\begingroup$ Egypt also had a period each year during which agriculture was impossible because the land was flooded, leaving a lot of surplus labor. It was also the best time of year for moving large amounts of stone by barge. $\endgroup$ Commented Oct 16, 2019 at 17:04
  • 1
    $\begingroup$ Your ideas are wrong, sorry. The ancient wisemen wisdom came not from autism but from contact with spirits. I find the reduction of their wisdom, the deliberate ignorance of they actually wrote, the belief that they didn't meant to say what they said and the idea that man like Plato, Laozi or Imoteph were wrong but some late industrial citzen is right quite offensive due the arrogance. They weren't idiots. $\endgroup$
    – Geronimo
    Commented Oct 16, 2019 at 18:35
  • $\begingroup$ @Sentinel do you have any evidence of such as system even existing much less working? preferably an argument that isn't circular. $\endgroup$
    – John
    Commented Oct 16, 2019 at 21:13


I don't think you could do it even if you used a shorter 'way back'

Let's try roman times:

  • Well organized society.
  • Lots of workers.
  • Has a working economy with division of labour and money. This last item makes scaling things up MUCH faster, since one wealthy person can command the work of thousands.

Even then you have some major problems:

  • You have a pile of books. Class sets?
  • How long does it take your 120 people to teach your 10,000 to speak English? Some people pick up a new language quickly. Most do not. Catch them as kids. In third world countries, with good community support, a teacher can handle a class of 30-50. If ALL of your 120 cadre were teaching full time, it takes 10 years to get 6000 kids who can read and write.

  • How long does it take to introduce printing? You're going to need paper. Look at the process to copy a book by hand, including making the parchment. A book's value is measured in at very least man-months.

  • You're missing a lot of trades. Your 120 people needs to include a whole raft of engineers. More: Historical engineers. You need a bunch of shade tree mechanics. Black smiths. Masons. Millwrights. Just what goes into making paper. How many whole industries do you have to make to make the paper to make the books so that you can make those whole industries.

Third world countries often skip forward to modern times in a hurry, but they are being externally supported. E.g. One project is to put a solar cell, a battery and a moderately bright LED in every home in a village. Tiny step that costs a few dollars per house -- less than the price of a land mine. But this allows people to work, and read after dark. But to provide that you need the whole infrastructure of the first world. This increases the useful waking time by about 1/3. Equivalent to extending their lives by a couple of decades.

Lots of third world projects to do things like make well pumps from local materials. Steel pipe. Parts of old cars. First world junk. When you go back, you won't have the scrap heaps to work with.

Huge problem of, "we know better" on both sides. If you haven't lived with change, anything new is a threat. Your cadres has to learn the culture deeply to effect change on it. In the last half of the last century agronomists bred a rice that had enough vitamin B6 to prevent the wide spread deficiency disease then extant in SE asia. People wouldn't eat it. Had a different texture from the rice they were used to. (My local super market has 15 different kinds of rice that are sold in 10-20 kilo bags. Our city has a lot of asians, from many countries and cultures.)

  • Lots of things aren't in books, but are skills that are passed down from one practitioner to another. There was a TV series about trying to recreate stuff based on te tech of the time.

Ok. So how would you do it, and how much could you get done.

  • Don't send them all to the same time. Start by sending a few -- 1-2 -- to, say 30 BC. Their job is to learn Latin as spoken in Rome. They come with a small pile of portable wealth to set themselves up. Probably not Rome but a villa outside the city.

Next people come 5 years later. (They can be 10 minutes apart at this end of history.) They come to the villa, and for the first 6 months learn Latin, and the local culture.

Big influx of slaves available from the Gallic wars. This group is buying slaves, and putting them to work building the buildings that will eventually become schools, factories etc. Probably best if this villa is on a river with enough of a flow to power multiple water wheels.

Power in Rome was based on wealth.

Some of your people pose as traders to convert future wealth into forms that are easily used as money here. Gold and silver work. I suspect that artificial gems are better. Coloured gems were more prized than clear. Synthetic sapphire (many colours) are about $1 each for a 1 x .5 cm stone. You could fake up a mine easily enough. Setting up a dye works to colour cloth would make enormous amounts of money. Tyrian purple was at least 3 times the price of gold at the time. Synthetic indigo (another prized colour) runs about $4/pound here. It takes a gram to dye a pair of blue jeans. There are a whole bunch of dyes that can be made with analine that are intense, cheap, and enduring. This is 1860's chemical tech.

Meanwhile, one of the ways you govern your slaves is to tell them that they are free in some number of years. After that you offer to pay them. While this is happening all the slaves kids are in your schools, learning to read, do arithmetic the new way (arabic numbers) and use logic. Books are still scarce, but slates dipped in wax work for temporary records and training.

Meanwhile, your historical metalurgist is trying to recruit the locals and teach them how to make better alloys.

You will need a massive priority list. Paper requires either sulfuric acid or lye, and cotton or woodpulp. Then you need screens to drain it on, rollers to fuse it. I suspect that paper was more critical to the explosion of books in the renaisance than the printing press was.

You're going to have issues with transportation. Steel requires coke, which requires coal. From Rome I'm not sure where the nearest surface deposits of either are. Probably NOT on the Tiber River. But you're going to need tons of it. Even today water is the cheapest way to move freight. Compared to ox pulled wagons, the cost per ton-mile is tiny.

I suspect that overall in a hundred years you could get a pocket of late 17th century tech.

Hmm. Not going to do all your homework for you. Get a good history of technology and figure out your path, and what bits you can shortcut.


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