Some questions focus on what the most important discovery will be (in the past), while others wonder if we can survive in certain time-periods. However, my question is - is it even possible to be able to go to the past and create inventions without dying ? Assuming that you end up in the Ancient Greek period, and that the magic that brought you there also allows you to speak and understand Ancient Greek (written and spoken) and gives you immunity to certain diseases. My question would be: Is it be possible to revolutionise that time-period without being killed by others accusing you of witchcraft or heresy? ( You can't just go and claim that Aristotle is wrong for example)

Note: Also assume that you are a near-genius level of intellect and you have great knowledge mostly in maths and physics.

  • $\begingroup$ become part of a already existing kingdom, considering your intellect, become the advisor to king/emperor. $\endgroup$
    – Chinu
    Jul 20, 2016 at 12:07
  • $\begingroup$ @Chinu : That is good, why not write it as a answer ? $\endgroup$ Jul 20, 2016 at 12:08
  • $\begingroup$ I believe it cannot be done, even with amazing technical know hows, 50-100 years is far too less to revolutionize ideas (needs lots of propaganda warfare), at best you can survive and live a luxurious life by selling technology. But I am hoping for a detailed answer of yes. $\endgroup$
    – Chinu
    Jul 20, 2016 at 12:14
  • $\begingroup$ @Chinu It wouldn't be that easy. See for example What could an average modern human achieve in medieval times? and follow the many links to other questions both in questions, answers, comments and sidebar. $\endgroup$
    – user
    Jul 20, 2016 at 12:24
  • $\begingroup$ Couldn't you get vaccines to protect you against the diseases and computer translation is pretty good now. If you bring a lot of some rare or unheard of substance then you could be very rich. $\endgroup$ Jul 20, 2016 at 15:24

7 Answers 7


Witchcraft? Heresy? You take Twain much too seriously.

Those are specific crimes with specific meanings, none of which are, "Creates cool and useful things." Even during the peak era for witch trials and as the Catholic Church was most active in its search for heresy, alchemy was a common (and fairly respectable) pastime among intellectuals. The idea that the pre-modern cultures feared every advancement is a myth of the Enlightenment. It makes for great fiction but has little historical precedent.

This is particularly true for the ancient Greeks, who enjoyed few things more than a good debate. It did not matter in Greek culture if you disagreed with Zeus himself - as long as you backed it with sufficiently eloquent sophistry. (Socrates was killed, not because he was impious, but because he was a political enemy of the new democratic regime.)

The answer to the question actually hinges on the infrastructure available. There is no point in inventing a cannon if there are no foundries that can build one, and no metals strong enough to hold up. There are very few "world-changing" inventions that are not similarly dependent on a whole panoply of other (often seemingly unrelated) technologies. Any meaningful advances will likely take years to hone, implement, and finally become influential.


In ancient rome/ ancient greek, it would be quite easy to bootstrap some scientific projects. That period already saw major mathematical breakthroughs and produced some significant scientific knowledge. Archimedes principle for example (250 BC). Architecture was well-developed.

As long as you made each step small enough, what you are doing wouldn't be magic. Of course if you presented microphones and loudspeakers and a working radio first, they might think you are a god or evil wizard, so choose wisely and make sure not to introduce too advanced things.

If you went to the dark ages, then you’d be in for a rough time, no matter how small your advancements are. its called the dark ages for a reason.

I don't have enough understanding of Asian culture to determine whether or not it would be a good idea to go to ancient China. They had advanced knowledge of black powder and rocketry, so it seems they were at least somewhat open to scientific progress.

Some things I'd consider safe:

Advance their knowledge of maths. Use Archimedes principle as guideline, and introduce Newtonian physics. Advance their knowledge of architecture using some new mathematical techniques. Slowly intruduce algebra and differential calculus. Advance their knowledge of materials in small steps, guide them to the invention of steel.

Once they have progressed enough, let them recreate the experiments of Ampere and Watt to have them discover electricity. This will likely be decades after you first arrived. I am not sure if their society would be ready for radio waves by the time you die. But thats a bit up to you. If you invented the letter press shortly after your arrival, they might have used it to further education and might have a young generation that is very open to more advancements. In this regard, the letter press might be your best ally to bring the society as w whole further, because it allows you to spread news and knowledge very easily.

This all depends on you being able to convince the ruling elite to trust you, gaining access to funds, protection and being able to spread your knowledge to other scientists of the same period, and so to give them ideas to pursue so that you don't need to come up with everything yourself.

In that spirit, your first few inventions should probably something that is useful to a ruler so that he wants it and more importantly, wants you to work for him. The more he trusts you, the more tangential projects you can realize.

  • 1
    $\begingroup$ What I like about this answer is the suggestiong of 'guiding' a society rather than producing artifacts for them to judge. With small steps like those you describe, you could likely get the full support of the kingdom/empire you're helping and lead to a time of great prosperity and wealth for them. You'd be the Elon Musk of their time. $\endgroup$
    – ktyldev
    Jul 20, 2016 at 14:18
  • $\begingroup$ You'd be the supercharged combination of Elon Musk and Stephen Hawking of their time, yes.b Thats why I'd consider the letter press quite important, because it would allow you only to give them ideas and steer them into the right direction, without having to do everything yourself. This means you can give credit to them. And you can get them on a good path for after your death. $\endgroup$
    – Polygnome
    Jul 20, 2016 at 17:48

Also assume that you are a near-genius level of intellect and you have great knowledge mostly in maths and physics.

Then you're boned.

The most useful knowledge you would need to survive and thrive in a past era is political skill and interpersonal communication, not "maths and physics". Knowing lots of stuff is useless unless you can convince someone else to do what you tell them.

In order to make any significant scientific change, you're going to need to find resources and/or people of importance. You're going to need to find a way to convince them to help you (or more to the point, convince them that you can help them). And when you start helping those people, you need to be able to prepare for attacks from their enemies.

You need to be able to walk the corridors of power without a scratch. Only then will you be able to put that "maths and physics" to any real use.

That's even true for mathematical improvements. You're going to have to invent zero and convince a bunch of geometry masters to give up everything they've worked for in favor of your calculus. That's not going to go over well unless you know how to influence/manipulate people. You're going to effectively start a reformation movement among the masters of mathematics of their day. And that requires serious leadership skills and the ability to know who's going to join you and who isn't.

A single person shifting a society is not an easy thing. And it doesn't happen based on one's knowledge, but on ones political skill. Especially since you're going back into a time which is completely unfamiliar to you.

  • $\begingroup$ This is what happened to Galileo. Sure he was smart, and mostly right, but he was also very grating and rude, and had a bad habit of pissing off his sponsors - including the Pope himself $\endgroup$
    – No Name
    Jun 14, 2022 at 9:06

Yes, it's absolutely possible and does not even depend on time travel, it is a universal principle that holds true in all ages and places.

The safest way to doing things that are dangerous to you or others in the way you describe is to secure the benevolence and protection of the ruling elite. Except for true religious fanatics, people are highly adaptive to even drastically new situations and realpolitik will trump dogma. If you manage to convince the right people that your inventions will consolidate their power, bring them great fame and riches, advance the position of their town/country compared to rivals, or give them whatever else they might crave, they will allow you to do a great many things, even things that most people would find to be repulsive for moral or religious reasons.


If you bring enough wealth with you people will let you do almost anything. If you want something that is cheaper in your own time... Metals like steel, aluminum made into weapons or armor better than theirs. Glass, mirrors or plastics. Spices and seeds. Some electronics? Any electronics must be powered by solar or wind up. Torches or long range radio communications would be useful. knowledge of races or other contests could let you bet your way to success.

Once you have a fortune buy a workshop, work out exactly how to make something (bring relevant info) then show it to top craftsmen and invite them round to show them what you did.


Become a blacksmith!

Without raising any suspicion, you can request all sorts of crazy materials from basic copper, iron, etc.. to animal parts, gems, engineering tools and (for the time) a high energy lab.

With this at your disposal, its not too terribly difficult to whip up wiring, motors and even transistors. Carefully find a trade partner who will keep you safe once you've built up while also making you both rich. At this time however only use your actual technology for making impressive alloys, maybe plastics, rather than sell motors. First you need to get an advantage.

From here you can start to hire more and more workers. In a short time you could build a small, primitive fleet of elite defense and elite craftsman. You're pretty much set if you play your cards right.


Depends on the time and place... Greece for example was fairly open, but you might find yourself dead for exposing the secrets of the mystery schools. If not that you have the issue of building up a number of technologies and spreading them enough which you probably couldn't do.

Rome had knowledge of up to around the 1930s level tech. They just didn't use it or it was blocked by imperial decree.

European Kingdoms would back you so long as you got results. The catholic church was more against wide spread knowledge that contradicted them, not inventings stuff.

Some of the US colonies you'd be able to advance very quickly, while others would burn you at the stake.

Asia in general you would end up in a lavish prison with everything paid for. You might be free to roam the town or travel, but you'd be under constant guard and all your work would go towards 1 lord or another. You'd be pretty safe and free otherwise save for the possible assassination attempts from other lords, but other than that you'd be fine.

The Golden Horde might be a problem only due to their policy of killing betrayers and so if you were working somewhere and they conquored it they might view it as you betraying that village/town and might kill you.

Arabia you'd never get what you need to really advance, even in the most lavish of surrounding you'd never get anywhere worth while to even remotely be considered "magic"

So... In most parts of the world and time you'd mostly be perfectly safe. The main problem is standard political moves that you'd find yourself in danger from.

Also, as someone with the knowledge and intellect to build a society and it's technology practically from the ground up to present day levels the main issue other than politics is skill and money. The majority of people, no matter what their level of knowledge is on particular subject, cannot produce the level of skill necessary for creating components for one of these technologies let alone all of them. The best you could do is create a cabal of people work with and teach them the practical aspects of things and then also write down all the theory about things. doing that, you might get to just before modern tech in a life time from Agrarian levels of technology. Noone has enough knowledge to get modern tech because it requires to many specialties and infrastructure to work.


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