You were born in Rome, when the Roman Republic was still in power. Your father is an upper middle class merchant and you are (or will be) the sole inheritor of his wealth.

One day, a mysterious stranger comes to town and offers your father his services as a tutor. He possesses strange contraptions, has a thick accent and is altogether otherworldly. You convince your father to employ him and he begins to teach you chemistry and medicine at a level unimaginable by your society (all the way up to our modern understanding).

You study with him for 6 years and he teaches you all that he can.

What can you do with this new found knowledge given that you want to advance humanity as much as possible within your limited lifetime?

Suppose that he teaches you up to the level of a modern doctor (M.D or PhD) and that you are

  • More or less benevolent (no megalomaniac tendencies)
  • But not entirely selfless (a man's gotta eat!)

EDIT: I do know of the other question regarding the time-traveling average Joe going to Medieval Europe. My question is different in three ways:

  • The character in question is not an "average Joe", he has sufficient familiarity with the customs and culture of his society and is relatively high up in it
  • The time period is Ancient, rather than the Medieval/Dark Ages
  • The knowledge conferred, is of a highly specific (Chemistry and Medicine) and advanced nature (M.D/PhD level) with sufficient thoroughness in the teaching to be beyond the realms of "average"

Seeing as many of the answers of that question deal with the stigma of being foreign (not speaking the language or knowing the customs) or just simple survival (given poor living conditions, and that the character has no wealth or status in that society) I think my question is different enough to merit consideration

In response to some of the answers, I feel I need to clarify things a bit:

  • You are answering this question from the perspective of the native Roman (not the mysterious, possibly time-traveling, stranger). The mysterious tutor disappears as quickly as he arrives.
  • 6 years may seem insufficient by today's standards of education, but keep in mind that these 6 years are not spent in a lecture hall listening to 1-3 hour lectures but on one-on-one tutoring sessions (6-8 hours/day) with a live-in tutor.
  • Where tools are necessary to prove certain things (like microorganisms) that are also not to unwieldy (simple light microscope is easy enough to carry, TEM is not), assume the tutor had one but that the Roman does not.
  • $\begingroup$ I believe this question is too broad as it's written. What can you do with the knowledge? Any of an infinite number of valid things. $\endgroup$
    – Samuel
    Commented Apr 7, 2015 at 1:41
  • $\begingroup$ Hmm, ok. I will try to make the question more specific then $\endgroup$
    – Dider
    Commented Apr 7, 2015 at 1:50
  • $\begingroup$ possible duplicate of What could an average modern human achieve in medieval times? $\endgroup$
    – Jim2B
    Commented Apr 7, 2015 at 1:53
  • $\begingroup$ It is very similar to the linked question. $\endgroup$
    – Jim2B
    Commented Apr 7, 2015 at 1:53
  • 1
    $\begingroup$ @Jim2B I'm going to second James comment. While I was first inclined from the question title to presume a duplicate I feel this is sufficiently different.to warrant it's own question $\endgroup$
    – dsollen
    Commented Apr 7, 2015 at 13:54

6 Answers 6


Your biggest problem by far here is going to be getting other people to believe you.

I'm assuming this mystical tutor is from the future? Given that, surely he must know that there will be problems getting society to believe what they're told. However, we've already done solutions for that on this site: see How do you prove you're from the future?

Once you've got everyone believing what you tell them, you also need to be able to keep that belief: if everything you spout is complete nonsense and the principles don't work when tested, you'll pretty quickly get executed. This is Ancient Rome. The solution to this is to take it all slowly, much as the tutor should have done for you. Teach the basics first and prove that they work. Then move on to other more complicated things that rely on the basics.

As for what the greatest benefit to society would be, it's a mixed blessing. All this knowledge could easily bring back penicillin, agricultural success, good housing, food security - and overpopulation. Instead of the global population exploding in the 1800's around the Industrial era, it'll explode in the new industrial age: what we call Ancient Rome.

What that does to us, today, is unknowable. Essentially, our current situation is brought forward so it happens in c.100 AD instead of 2015 AD, giving us another 1900 years before we get to today. Scientists are predicting, as always, several different outcomes of overpopulation:

  • The Earth becomes wildly overpopulated, food is scarce, people die, and the population drops (then the scenario repeats)
  • We start implementing strict 2-child or even 1-child laws. This stops or reverses growth - for every couple, you need 2 children to sustain the population.
  • ???

There are plenty of people making plenty of predictions, and nobody knows who's right.

Summary: it brings 2015 to the Romans. Great for them, perhaps not so great for us.

  • 2
    $\begingroup$ You left out, "We move off this rock and conquer the galaxy for the glory of Rome." $\endgroup$
    – Perkins
    Commented Aug 5, 2016 at 0:01
  • 1
    $\begingroup$ The contents of my pockets would prove to a any bright mind that I am from the future, assuming anybody could be bothered to check. $\endgroup$
    – Joshua
    Commented Aug 28, 2017 at 21:44
  • 2
    $\begingroup$ 5 years late to the game, but please note that where populations are growing massively in the modern world are exactly where development is slowest. Every first-world industrialized society is fighting the effects of low population growth. High population growth is found only in less industrialized areas with less access to modern medicine and practices. Introducing the mind set and practices into ancient Rome might spur a temporary population boom, but would almost certainly settle out following the pattern of modern societies. $\endgroup$ Commented Mar 11, 2020 at 2:29

I think the first thing you and your time travelling chemist should do is go into producing dyes, since that is where industrial organic chemistry got its start. The chemistry is relatively easy, and the products are readily saleable, without smacking of magic. See the book "Mauve: How One Man Invented a Color That Changed the World" http://www.amazon.com/Mauve-Invented-Color-Changed-World/dp/0393323137

  • 1
    $\begingroup$ I like how this answer goes beyond just medicine and saving people's lives. The Roman elite would pay big bucks for new dyes. And the character could use the money to fund other initiatives. $\endgroup$
    – Kristy
    Commented Apr 8, 2015 at 11:44

The biggest advantage he could offer to the modern world is sterilization and antibiotics. There were MANY diseases which could easily have bee prevented with a better understanding of sterilization and sanitation, entire epidemics could be stopped with these basic ideas. However, even a noble may have trouble convincing others of the power of sterilization, unless of course he has already come out with another miracle medicine which proves he knows what he is talking about.....

On a clearly unrelated note, as per Could a modern times time traveler produce an antibiotic in medieval times? and Will this approach work for a time traveler to recreate penicillin? he should have a pretty easy time finding and recreating penicillin if he has full knowledge of it. He may have some difficulty culturing it, but it could be saved as a miracle drug for the rich, even if it can't be mass produced enough to help the poor. Perhaps he could arrange to have samples of penicillin taken to the poor villages and tell them to start growing and maintaining their samples on their own at their own expense if they want it or something.

He would no doubt make a massive profit from penicillin, since it is limited in how fast it can be cultured it will be expensive, but any noble would pay for it, so he definitely has a sellers market if he wants to turn a profit. He could be more giving and focus on getting it to as many people as possible while still turning enough of a profit to take care of himself though, nobles will pay massively for this!

If he still needs help convincing others that he knows what he is doing he can Have a microscope built and prove the existence of germs (When could a microscope first be made?)

By this point he will have a name for himself and people will accept he knows what he is talking about, even when it comes to medical details that are harder to prove with present time technology. This should allow him to teach what he knows to others, with them believing him. The best way to do good is simply play tutor, teaching his knowledge to others so that it can expand to all doctors. He can only do so much with his knowledge alone, but once you have dozens of young nobles trained by him they can all focus on different avenues for how to save lives. Spreading the knowledge and recruiting more does more long term good, and obviously he can charge for his tutoring services to more then cover his food needs.

There would be a bit of a down side to this though. With so many deaths prevented there would be many MANY more mouths to feed. They may discover that suddenly the current crops and agriculture isn't able to keep up with the increased demand. Ideally he would work ahead to spread word and encourage moderation in the whole procreation thing. If he brings the secrets for basic herbal birth control that would mostly take care of that issue though.

As a nitpick though, 6 years tutelage is NOT enough time. Just the time spent in college for someone to get a general medical degree is more then 6 years. However, by the time you enter college you know about germs, viruses, sanitation, evolution, cells, human bodies, organs, DNA, etc etc etc. We learn quite a bit in high school that furthers our college, and he won't have any of that. It will take quite awhile for him to have even a basic high school education level of understanding in these topics. Remember he has to learn a good bit of math to understand advanced science such as biology, and he needs some physics and chemistry to understand biology. To fully grasp it there is allot to learn. Though you could argue that his tutor is focusing only on teaching him the most useful bits he can use to help others, while allowing gaps in his education for things that can't be easily implemented in his present day. Or that the tutor is still available to teach him even as he is starting down the road to revolutionizing the world, and is thus a resource to help gain details and specifics he didn't yet know (such as how does one recognize penicillin on sight).

  • $\begingroup$ Would be interested to hear your thoughts on the impact of antibiotic resistant bacteria showing up two thousand years ago. I wonder if that might actually make things worse in the long run because our other tech wouldn't be able to keep up with the mutations. $\endgroup$ Commented Apr 7, 2015 at 14:47
  • $\begingroup$ @DanSmolinske i highly doubt it would make thing worse. Obviously until you reach the age where penicillin was created you have only a gain, you have a tool that you didn't have before, even if it drops in effectiveness over time a quasi-effective tool is better then none. Worst case during the brief period of time between when we had discovered penicillin but not any other antibiotics in our own past this world would be worse off, since they couldn't use penicillin and need replacements but I think the lives saved over all the time in the past would be worth far more then that brief time. $\endgroup$
    – dsollen
    Commented Apr 7, 2015 at 15:26
  • $\begingroup$ @DanSmolinske furthermore penicillin is not the only antibiotic fungus. See my question about how to try to recreate penicillin if you don't know how, you can still do those steps! Effort could be made to keep finding new natural antibiotics that way as the current degrade in effectiveness. Sure your antibiotics would be less powerful after resistance, but still much better then nothing!! Besides, the use of antibiotics helps prove the traveler knows what he is doing, from there he can teach sanitation which will do even more good then antibiotics! It's a means to an even greater ends. $\endgroup$
    – dsollen
    Commented Apr 7, 2015 at 15:29

We have a lot of foundations that we kind of take for granted. There is kind of an expectation that once someone enters med school they have some basic understanding in anatomy, biology, math, medical theory, etc.
You can do on the job training, but going from apprentice to master takes a really long time.

Is this from the point of view of the time traveler, or the student?
Since he's a time traveler, it seems like he could skip around a bit to build the foundations.

Travel to X and teach a few nobles basic math and maybe a new number system. (the Romans had addition and subtraction (clumsy because of the numerals), but not multiplication and division)
Travel to X+10 and teach advanced math and germ theory.
X+20 and share the discovery of algebra, calculus, and antibiotics.
X+30: engineering, materials, and basic chemistry.

He'd be a something of a legend, arriving in town from who knows where, taking a few select students and imparting knowledge for a few years, and then disappearing again.

The knowledge would spread during his jumps, and people would build on it themselves, so that each time he'd have a higher place to start from.

You've heard the phrase, we stand on the shoulders of giants? Well, those giants are standing on the shoulders of other giants, who are in turn standing on others, and so on. The traveler would have to jump start it a bit to be really effective.


This Roman could change the world just by teaching the scientific method till he died. The medicine and chemistry might be draws to get people to pay attention to him but the greatest thing he can teach is the scientific method. Every major advance from the Great Enlightenment onwards are a result of the scientific method. It is the great enabler of human progress.

Scientific Method

The philosophy of taking a hypothesis and testing will change the world 1200 to 1400 years early. Granted, humans have been doing this kind of basic experimentation for millennia but the definition/codification of the method will enable its spread. This one Roman who received the original education can't do much, but the idea of how to test ideas can change the world.

Chemistry and Medicine

Sure, anything the Roman can teach to his countrymen will have a significant impact. Things the Romans tried to do will now work. They'll have better metallurgy which allows all kinds of fun things. An introduction to physics, a number system that allows easy multiplications and the concept of zero will be HUGE!

  • $\begingroup$ It's notable that the scientific method by itself wouldn't have too much of an effect. It requires a general attitude of "let's vivisect nature to see how it works", which was a product of Christianity. The second-century Romans considered that sort of attitude anathema. $\endgroup$ Commented Apr 8 at 14:55

Others have mentioned some of these, but the basics are:

Medicine: Microscope + Pasteurization + Penicillin + Anesthesia + Sterilization + Blood typing for Transfusions gets you pretty far, also draining swamps (sorry wetlands lovers, mosquitoes are not the dominant species)

Agriculture: Better plow, seed drill, thresher, crop rotation

Textiles: Spinning wheel, Jacquard loom, sewing machine

Transport: Steam engine, railroad

Refrigeration: Shades of the movie "Mosquito Coast".

Communication: Telegraph (battery, wire, simple electricity generation)

  • $\begingroup$ Movable Type and Block Printing. $\endgroup$
    – Oldcat
    Commented Jul 20, 2015 at 23:37

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