The world I am building focuses on one particular nation. From some point in its recent history (10-20 years ago) many beneficial changes have improved society overall. Although it may not necessarily be known by most people all of these changes, in one way or another, originated from a single person from a more advanced world.

My question is about the exact nature of these changes. What could these improvements have been?

The world has a technological level of at best advanced cultures such as the ancient Romans and Greeks, China or perhaps Egypt.

Despite saying so, this does not apply to any single nation in my world all at once. There may be those who have a better understanding of architecture, of metal working or any other areas. There is no single nation close to the peak of the past empires I mentioned in more than a few aspects.

Magic does exist, but is irrelevant for this question at large - just assume that they basically have a free pass from truly bad injuries or illnesses given swift treatment.

The person who instigated these changes/improvements comes from a different world with modern technology like ours.

I will explain what that person had available at a minimum and by what criteria an answer would be measured, lastly I'll provide a few simple examples of what they could have done.


  • the person instigating changes comes from a modern society with modern technology, however, they have brought only handheld tools with them to the current world
  • they are studied in informatics and therefore excel at solving and approaching problems in a structured manner; basically, they're very smart and capable of applying those smarts to any context
  • in return they do not have any significant experience with natural scienes; given proper explanation they are capable of understanding all of it eventually but they still wouldn't become capable of metal working or mixing chemicals safely just like that, even if they understand how it works
  • they do have a big digital library of any information with lots of instructions (+ pictures for some things) they can access, and take notes with which is, however, largely superficial knowledge and many gaps in more advanced topics; in other words: though they may not be capable of implementing anything on their own they could still explain stuff to professionals (e.g. explain the requirements of a watering can to a proper metalworker even if the concept of a watering can was previously unknown) based on the more or less superficial knowledge they get from their library (only they can read/access it), but they couldn't really learn to distinguish between different kinds of sands on a level precise enough to guarantee the success of chemical reactions
  • they can have direct contact with anyone who would most reasonably be capable of implementing their information; if they realize that some domain has large woods full of cork oaks they don't use they can make a case for producing cork towards whoever is in charge of that domain; or if they came up with a gimbal (in theory) to improve compassess at sea they could directly request this of skilled craftsmen that are the closest to being able to make it happen
  • they are still limited by current, local technology levels; or in other words, asking the most qualified people to make something happen won't guarantee success
  • the world works just the same as the modern one and also ours in terms of stuff like human anatomy, chemical reactions, eadible and non edible plants and all that, so don't be concerned with science suddenly working differently there then here

This is rather broad perhaps, but the positive changes I need don't have to be world changing or super generally applyable (although they could).

Answers will be evaluated not based on the societal significance of the proposed improvements but rather on the following:

  • Is it an actual improvement/novelty over something? E.g. developing a composite bow would be an improvement over a society that only has single-material bows, whereas introducing glas manufacture would be an improvement over a society that did not know of a neutral material like that before.
  • Is it possible to break the simplest application of that improvement down into steps that can be executed even by an amateur? For example, if the society did not know about magentic compasses any modern person could brush a small piece of metal over some hair place it atop a leaf floating on some still water and make a demonstration of how that piece of metal always points in the same direction. A sophisticated compass could later be produced by craftsman based on the same principles, but our modern person needs a smallest demonstrable case to incite positive change.
    • In case of improvements of related areas to already existing technologies (i.e. introducing glas to a society that knows of forging) the simplest application should reasonably be doable for a good craftsman within the related, already existing profession.
  • Could the effects reasonably be felt within a span of right away up to 10 or 20 years? For example, introducing cork could give you proper positive results with the second harvest (which would be 8-12 years after the initial harvest) so within 15 years it would certainly be possible that people in certain crafts would have come to consider this a good change overall even if the large majority may not yet be aware of this new material. Explaining fore and aft sails could arguably give positive results even within a few months, if previously boats/ships had to rely solely on tailwinds or rudders, for they could almost instantly make use of wind from more directions than previously even if learning how to properly control it may take longer.

Also, it is not important that the modern person is remembered as the one who inspired the improvement, but it is not harmful either.

I did kind of include several examples so far, so I will give two more to further show that the scope doesn't have to be epic:

1. First, imagine a society that makes good use of water wheels for its agriculture and other sectors after the technology was naturally introduced by some more developed nation over the years. The society now wonders why their wheels break a lot faster on average than in the country of origin, despite perhaps both being made of generally the same materials. The modern person could notice that this society doesn't attach any importance to the number of teeth on the wheels and just go with whatever, thus they propose to have any two gears that link into each other to have a coprime number of teeth. This way, on average, their wheels will now have a longer life span due to spreading the tear and wear as evenly as possible.

2. Secondly, imagine a society that has glass working but mostly just presses them into forms. They also really appreciate spherical marbles as jewellery but can't quite produce any true spherical forms. The modern person could propose building a spiral like slide, and letting the molten glas mixture flow down this slide. That way, it will naturally form into balls on its way down, and it would be easier to adjust this technique to gain marbles closer to true spheres.

Lastly, I want to mention that the society of this nation itself is not yet fixed in place. Make any assumptions necessary for your answer to make sense, e.g. assume it has enough rivers to be dependent on waterwheels if you wanted to improve waterwheels, assume it doesn't have any kiln capable of continously withstanding 2000°C if you want to explain how to build one for the ultimate BBQ.

Know that I would prefer any improvement not involving electricity as its main component or some other tech that would probably spark an industrial revolution of a rapidly world changing magnitude. So if you have figured out how to do proper atomic fusion in simple steps that's awesome (do tell me about it =) ), but a bit too drastic for the purpose of this question.


A modern person with minimal equipment but vast amounts of superficial knowledge improved ancient roman level society in the past few decades. What did they do and how did they instigate it?


closed as too broad by Mołot, Hohmannfan, L.Dutch - Reinstate Monica, Aify, Lio Elbammalf Mar 24 '17 at 13:02

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ sounds like either Let Darkness Fall by Sprague de Camp or A Connecticut Yankee in King Arthur's Court by Twain $\endgroup$ – John Mar 24 '17 at 0:14
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    $\begingroup$ Your setting confuses me, you say a person from an advance / modern society gets to a world in ancient times as you say, "They wouldn't become capable of metal working". In addition, "they do have a big digital library", and they can access that - this suggest they have reading and writing, so perhaps they did skip the metal ages... but with the knowledge of the library, why did they not pursue mining? - also is this library public for everybody or something for the ruling class or something like that? (They didn't create the library, right?) $\endgroup$ – Theraot Mar 24 '17 at 0:17
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    $\begingroup$ The big problem you have is most people do not know how modern technology works or how modern materials are made or processed. knowing how a revolver works does not help if you don't know how to make the quality steel needed to make reliable guns or the ability to identify needed materials. The people you meet will not know what oxygen or saltpeter is so you are own your own to find/make most materials and chances are you don;t know what they are. $\endgroup$ – John Mar 24 '17 at 0:17
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    $\begingroup$ Honestly it sounds like you already know what you're after, so what's the question? $\endgroup$ – apaul Mar 24 '17 at 3:33
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    $\begingroup$ A specific culture or technological level would be helpful, your listed civilizations span most of human history. Water wheels, germ theory, crop rotation, ect. would each greatly change some of them and barely affect others. $\endgroup$ – John Mar 24 '17 at 15:04

I will assume that the world to be changed is similar to the Mediterranean Late Antiquity. To fix things, let's say that the benevolent time traveller arrives in Constantinople at the beginning of the 6th century.

First of all, since in your story they already have magically advanced medicine, in this world Justinian's plague won't have the devastating effect it actually had in the real history; this means that the Classical World would most likely survive for a very long time. In the real world, that plague was the event that sealed the fate of the Roman Empire; with more than 50% of their people dead and their economy in tatters they were easy prey to the Arabs in the 8th century.

Now, what easy technological advancements could a benevolent time traveller bring to the 6th century Romans? They had fore and aft sails, but they had no idea how to use them on large ships -- large transport ships used square sails, fore-and-aft rigs were used on fast couriers. They had perfectly fine bows. They had glass; the most important immediately useful technical advance here would be making of sheet glass for windows and such: does your benevolent time traveller how to make sheet glass by floating it on a bath of molten tin?

Guns, steam engines and steel

Guns come first. Armed with cannons, the Empire won't lose Syria and Egypt, thus preserving its economic base and decisively stopping the fulminant spread of Islam under the Rashidun caliphs. Armed with cannons, the Empire would restore its dominance over Britain and Gaul and Germany, which is extremely important because the Mediterranean world lacks any natural resources other than fish and stone and (by that time already almost depleted) wood. If you want coal and iron and zinc and copper and silver and gold the Empire must have Britain and Gaul and Noricum (that is Austria) and Bohemia.

Any self-respecting benevolent time traveller knows how to make gunpowder and how to cast bronze cannon.

The Romans (who by that time spoke mostly Greek, but they still called themselves Romans) knew how to smelt iron, but did not have blast furnaces, so they did not have cast iron. They did not know how to make steel in any useful quantity -- maybe the benevolent time traveller might consider introducing finery forges and puddling.

Importantly, the Romans had very little use for coal. This is understandable, since there is very little coal around the Mediterranean. The time traveller may try to convince somebody to go mine for coal in Britain, because without coal steam engines and steel are non-starters.

Steam engines to power ships and possibly railroads would propel the Empire to the status of a sole world superpower.


In the real history, the industrial revolution began with textiles. In the Classical World textiles were very expensive.

They did not have and would have very much appreciated (in increasing order of mechanization) spinning wheels and spinning jennies and water frames and spinning frames.

Cotton was rarely used, because they did not have cotton gins. Cotton gins are really low tech, but they would revolutionize the usefullness of cotton. Egypt would became a large cotton producer a thousand years ahead of time.

The logical next step is the power loom. Spinning jennings and power looms would liberate a large amount of women to participate in other activities, essentially increasing the available workforce by at least 50%; and they would crash the price of textiles, thus improving the standard of living of just about all people.

Other things

In no particular order: universally standardized units of measurement, metal lathes, steel saws, magnifying glasses, telescopes (very useful at sea), magnetic compasses, cutlery, canned food, refrigeration, double-entry bookkeeping, paper, printing presses (easy to make and explain, very very important and with immediate effect), postal services, perspective drawing, Portland cement (which is essential if concrete is to be used on a wide scale), algebra, stirrups, horse collars, glass chimneys and kerosene lamps, gas lighting, police forces, sextants, the lunar distance method for computing longitude at sea, logarithms and the slide rule...


Assuming that by "improving a society" you don't mean "developing mass destruction weapons so we can enslave the rest of the world", I'll skip weaponry completely. A normal bow is a useful hunting device. A composite bow only use is killing (armored) people. Hardly "advancing" a society.

Since they have magical medicine, If I were the time traveller I would be much more interested in learning it that in explaying anything to them, but anyway that rules out basic hygiene and medicine.

Then, IMHO, the most useful inventions to advance that civilization would be:

  1. Mouldboard plough and set-aside techinque: most of these civilizations you mention (Egypt, Rome) would resort to hoe-farming. Introducing the plough and the concept of rotating cultives and set-aside land would increase food production threefold. If your civilization is set in a more wet environment (northern France and Germany, Britain), the mouldboard plough by itself yields three times as much production as they were having.
  2. Compasses and sextants: simple and easy, but it would send its maritime operations (exploration, fishing and naval warfare) to a new epoch. I would add chronometers, but these are quite more difficult to make.
  3. Steam engines: while the first ones aren't going to be much efficient due to mechanical problems and lack of condensers, once they got the concept right you could start a steampunk civilization in a couple of generations.
  • $\begingroup$ You're right about not wanting to go into weapon and conquering territory. The composite bow was an example I came up with cause my alternate world does have more ferocious animals (dragon like lizards and lots of them) making the bow quite a good improvement to life. $\endgroup$ – vruvre Mar 24 '17 at 11:55

Introduce them to slavery. Nah, I'm kidding. Introduce them to the notion that slaves are animals and can be treated as such.
Each country you mentioned have a large portion of their wealth build on slavery.

Then look in the library for "best materials in the world in the xxx time period". For example Persian steel was far superior to that produced in Europe. Go there, learn how they made that steel, come back, improve everything that have to do with steel (that also means army and your conquering capabilities).

If you have library you have also access to geological maps and placements of rare materials. So you can quickly and economically try to mine those. Also your war expeditions would be targeted to specific locations rather than just owning land mass.

Artificial fertilizer - don't mind the "back to nature" movement. Fertilizer is much better than manure. Also one bag of it yield more result than cow shit. So you can have a)more crops from the same area b)crops from terrains earlier uncultivated

Medicine - you can have penicillin, aspirin and other easy to produce things that improve your country health, work time (healthy worker is working worker) and production time (painkillers are good both for working your slaves to death and turning your soldiers into machines)

With glass you can introduce production of glass sheets so your houses and buildings can be lighter, faster to build and can have glass houses. With glass you can produce containers so you can improve food storage.

And lastly - if you have water wheels you can try to create electricity which in turn can be used for faster communication (radio), longer working hours (light bulbs) and some automation.


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