This is somewhat related to my previous question, but not enough to just let the explanation slide. So, here goes: I've ended up in a medieval world, again, and I want to advance it as much as possible. This time, however, I inexplicably have my phone, and it even more inexplicably can connect to the Internet from the timeline I just left. Now,

  • Assuming my phone somehow stays like this indefinitely, how far can I progress the technology level of the world in my remaining lifetime (assume about 60 years)?
  • Or, assuming this is only a temporary side effect of my time-traveling (or my phone runs out of battery), can I copy enough information down to paper in the remaining few hours I have to make any significant difference?

Clarifications, because they were requested:

  • The world in question isn't Earth in the past, but an unconnected world in medieval stasis, which rules out leaving deposits to buy help in the future.
  • Though generic answers are also appreciated, the specific world in question is the Redwall universe, as specified in the previous question. Furthermore, the character in question is a wolf, which is particularly rare in the Redwall-verse, so there won't be any danger from the populace of woodland critters beyond a few funny looks.
  • The character in question has an as-yet-undetailed generic duffel bag of "survival supplies." If anything necessary for your answer could rationally fit in this, go right ahead.
  • $\begingroup$ IMHO... no. A modern phone battery will last you 2days if you are lucky, if you had the perfect search capabilities (i.e. not unsuccessful searches), and were scribbling 24h (which assumes you have instantly access to writing materials, NOT trivial in medieval setting), your best bet would probably be about improving health conditions (fairly easy) with things like food preservation/hygiene. Most of progress relies on electronics/mechanics, so you need good metallurgy and chemistry before that. If you can build a hand-crank-based battery charger, you win. $\endgroup$ Feb 22, 2016 at 11:56
  • $\begingroup$ youtube.com/watch?v=oJpH4FxA57g this is how you charge your phone $\endgroup$
    – King-Ink
    Feb 22, 2016 at 12:51
  • $\begingroup$ Suggestion: to avoid all posts revolving around the time limit or power sources you may want to say that you also have a solar charger:solarpowerbeginner.com/images/solar-phone-charger.jpg $\endgroup$
    – Murphy
    Feb 22, 2016 at 13:15
  • 1
    $\begingroup$ Lepidolite, this is an interesting question but could you put more restrictions around your scenario? As it sits it is very broad. People could answer about ways things will fail, or a prioritized list of tech to research, or a whole host of other things. $\endgroup$
    – James
    Feb 22, 2016 at 15:16
  • $\begingroup$ My reccomendation is just to write stuff down, instead of asking questiins on stack exchage. $\endgroup$ Feb 22, 2016 at 15:28

3 Answers 3



You're going to run into a few obstacles with your device pretty quickly. There are many more obstacles (language barrier, health, etc.), but other questions cover that pretty well. This is just about the device itself, and related incidents.

Battery life

Your phone will likely run out of battery in only a few hours of use. Unless you can charge it, your phone isn't going to be much use. You might be able to write down some basic schematics for building a generator and a map of ancient lodestone deposits, but even with that it will be a long time before you get a constant 5 volt supply to recharge your phone.

The best fix for that would be to bring a solar charger, a hand-crank charger, or a camp stove charger. The stove would be best, then the hand crank, and finally solar power.

However, batteries tend to decay over time, leaving less and less charge. Eventually, you'll need to be plugged in all the time; unless your charger can supply enough power to keep the phone running, your phone is dead.

Physical damage

Your phone is going to take a beating. Life in medieval times is not easy. It will not only get bounced around a lot more, it will also have to survive humid or wet conditions, and dirt and muck getting on it and in it. You'll want to get a hardened, waterproof pouch for your device.


Find some powerful allies, because without them, you're going to lose your phone, and maybe your life. The ability to create light from the palm of your hand, steal images of people, and display YouTube comments will have your phone labeled as a device of the devil faster than you can say "4chan". You may lose your freedom either way, but it's better to be a servant of a strong master than dead, right?

What now?

So now you have a phone, a charger or three, a benefactor, and a fully charged phone with a 3G or better connection to the internet. What now?


The world is at your fingertips. The internet is full of schematics, DIY, and how-to manuals. Anything you could dream of is available. What's more, you have access to tools like message boards, forums, even VOIP! Where to start? What would give you the most output?

Start smart

Sure, you can't order from Amazon, but you could call historians, engineers, and mining companies. And with the ability to contact people in the future... make them do your work for you!

Begin an investment account. Give a big box to a trusted figure, to be opened at a certain time; do your research online and find the most probable methods of beginning a bank account, accessible to you in the future. Starting with a few dozen copper pieces in each account, instructions to buy or sell, and so on, you can amass considerable wealth.

If your efforts to make yourself rich (albeit through time and the Internet) fail because you aren't able to affect the timeline on the Internet, don't lose hope! There are lots of ways to make money; simply acting as a link between times and/or timelines will surely net you at least a little money. You may be able to make money from selling pictures, or raise funds on sites like GoFundMe or Kickstarter. If nothing else, posting on Worldbuilding will get quite a lot of attention (hey, wait a minute...).

If you're rich, you can pay people to research for you! Even with a limited battery life, you can stick to receiving emails detailing the best steps for you to take, saving battery life since you only need to turn on your phone once a day or so. From there, it's up to you where to point your resources, though comfort, weapons, maps to mining resources, and so on will make your host rich, which keeps you safe.

  • $\begingroup$ While the artifact investment seems like a good business venture, the problem with it is the branching paths inherent in time traveling. If I managed to end up in a medieval world, unless the timestream is strictly singular, chances are that I won't ever be able to leave anything for the present era, because that's simply not the way the future will run. $\endgroup$ Feb 22, 2016 at 16:12
  • $\begingroup$ Good point; edited to include that. $\endgroup$
    – ArmanX
    Feb 22, 2016 at 17:08

Assuming you've solved your power requirements and you're well received by the people, you want to follow the path of highest productivity. Kick in another Moore's Law (but for the whole of technological advancement), if you will.

Information Science took a great turn in our own time due to the advent of a certain mechanical loom in 1801 known as the Jacquard Loom. The loom was controlled by a set of punched cards with a card corresponding to a row of design when it was weaving fabric.

Punch cards executing a sequence of instructions is familiar to anyone with a love for computers, and this is a good starting point to anyone in the Medieval Era.

By taking some pages out of historical inventions that lead to the increase of productivity and innovation to new inventions, you'll have faster technological progress. You can distribute the knowledge on your phone, and start with rudimentary computing machines, the assembly line, useful factory set ups, etc. Anything that makes it easier to do other things.

Following that spirit, you can also put effort into energy that allows the production of materials that would allow for even better energy and even more production of materials.

Get a runaway train of technology running, basically. With these new tools, the people will start being more and more able to contribute with you. You can use your first machines to store and distribute (printing press, perhaps) the information you have so you have communities investing and sharing in the technological growth in parallel.

You want to focus on things that makes your technological growth exponential.


I like the limited side effect of time travel as the explanation for your information pipeline. It also adds a sense of urgency. As was pointed out in the comments, writing material will be hard to come by so I think you would be best served grabbing some facts and concepts while your connection lasts, and then seeking the business men who would benefit from those and making them allies.

A bit of sand and better oven design will make purer metal for the smiths. Something already learned and forgotten in the time/area that you are talking about. Ask a smith to permit you to make a demonstration behind his shop, no loss to him as he will get the better metal and the knowledge and you just want a friend.

Alcohol kills germs, make sure you know how to make a still. Distill some beer for purer alcohol. Vodka uses potato starches instead of barley starches. Methanol uses wood instead of food stuffs, and makes you blind if you drink enough and dead if you drink too much. But methanol (wood alcohol) burns and disinfects as well as ethanol (whiskey, vodka, rum) so it is useful to you. You now have disinfectant. Also, having a stable liquid lamp fuel will be handy. You already have the concept of germs and why people should use soap. Dont try to tell anyone about germs. Just proving the action-benefit connection is enough, and a decade down the road you can help teach the cause behind it.

Seek an audience with a land holder, and tell him you can increase his land's yield and the longevity of his serfs at the same time. Crop rotation will increase the yield. Start to build a new village for this land holder's workers, with very specific (but still open) sewers. You probably don't have time to study municipal plumbing, but you know water runs down hill. By getting the sewer out of the middle of the street and telling people to wash upstream of where the sewer connects, you can increase health.

Now you have a land holder protecting you and a smith with a good oven who is your friend. Time to advance science. The largest single contribution to science in that time frame was the invention of clear glass. Now, there might already be glass artisans in Italy, and Venice by law would kill any glassmaker that tried to leave. But you, being a man from the future, know the basic concepts of lenses. Also, clear glass largely enabled the advancement of chemistry because color reactions could be observed and measured, etc. You need your smith's better oven with white sand (or crushed quartz, same thing) and limestone (powdered, prevents water from getting through) and some soda ash (baking soda low roasted for awhile, reduces the temperature needed to melt the sand). I think the ratios are around 7 units sand/1 unit limestone/1 unit soda ash, but you will find that information in the 30 minutes you spend reading on this. The whiter the sand, the clearer the glass. A long metal pipe to dip in the molten glass, blow a bubble, spin to make round, and you have cups/beakers.

The medieval nobility wear stilt-like clogs to walk through the filth in the streets, as the only plumbing they have is the trench that runs down the middle and frequently gets clogged. The black death came from the fleas on the rats that lived everywhere. By removing the filth and trash from where the people are, you can remove most of the rats and prevent a lot of disease. I have toyed with the idea of a steam engine powered river ferry / gondola, fuelled by the filth shovelled out of the streets.

If you can get a vague knowledge of trade routes for foodstuffs, do that. Food is an excellent motivation for the people in power who are bored of their local flavors. The reason for the British empire in the age of exploration? Gold and ivory from Africa, spices and silk from Asia, tomatoes and chocolate from South America, furs from North America. Of course, the easiest metal mines will be the most important geographic information for your immediate technological advances.

Conclusion: Find the details of a few vital inventions as fast as possible, and then make friends with the people who best benefit from those. Be quick to defer honor and respect so the bishops and lords do not get jealous and kill you. I think electric revolution is too much of a leap, needing too much metal and industry in place already, go for steam. Geography knowledge will help you when it is time to scale up. Insist all your food is well cooked and avoid the delicacies of the time (calf brain pie leads to mad cow disease).


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