I can’t believe no one has mentioned this yet. It’s so simple: Sewers. That, and probably military tacytics, and how to make good steel, and knowledge of fortification. I doubt that I could do gunpowder. Maybe a low-tech stem engine would be possible, afer all, the greeks almost made one.
The Romans definitely had a good sewer system – you can see parts of it in Rome and Pompeii. I don’t know what happened by the tenth century, though. Sewers are the kinds of things, I suspect, that had to keep getting re-invented.
Your average person would have little knowledge of medieval military tactics, and without modern weapons, modern tactics of warfare would be pretty much useless.
Steel varied in quality, but overall, I doubt very much your average person would be able to improve upon medieval metallurgy in the creaiton of weapons at least.
Fortifications, again without modern weapons, castles were pretty much excellent at this already, how would you improve them?
There’s archeological evidence of stirrups in Europe from an 8th century burial in Slovakia, and in Sweden prior to that. Supposedly, they existed during the reign of Charles Martel, when the verbs scandere and descendere replaced Frankish verbs insilere and desilere, indicating that stepping rather than leaping was required to mount a horse.
Such a ringing endorsement! 
(and it’s lno, not Ino!)
Ah. Missed that.
IRT heliography, it’s been demonstrated that some native Americans did in fact use heliography, using mica ‘mirrors.’ Modern heliographers have found that mica is actually easier to use, albeit with less range, than silvered glass. The mica has a softer focus, and so you needn’t be so precise to get your flash on target. OTOH, it also means that more people outside the exact line of sight can see what it is that you’re signalling, if they can read your code.
Also, there’s some evidence of heliography from the time of Hellenic glory - accounts of signalling with polished shields.
[hijack]Does anyone else think they could make a MacGyver TV movie out of this?[/hijack]
Am I the only one who got this joke? Cracked me right up!
Globe Theater leads to sewer systems?
A good book about this type of future to the past event is the 1632 series by Eric Flint. Take a West Virgina mining town from the year 2000, and put it in the middle of the 30 year war.
Ha! Didn’t even see that one.
Medicine leads to Shakespeare?
Grr, chique left herself logged in. From now on all Doper guests have to use the other computer…
Manufacturing techniques like mass production, standardized parts, just-in-time, ABC distribution, use of standard deviation in forecasting, production planning, specialized higher capacity workstations, flexible tooling systems. Many of these techniques would apply even to primitive manufacturing systems.
:o :o :o :o :o
I’m sorry! I forgot!
Teach 'em how to build a 920’s style death ray?
What would that be, a bunch of mirrors designed to reflect the suns light? I heard about a mathematician in ancient Greece using that as a weapon, a row of mirrors were placed on the shore and used to set enemy ships on fire. Supposedly it worked too.
The Mythbusters tried to build one, but it never did anything more than heat up the target boat.
I’m troubled by the emphasis on technological innovations, without any considerations of what purpose they’d serve. It’s all well and good to introduce more sophisticated hardware, but where would you introduce it, and what would be the long-term consequences of supplying them with this knowledge? We could be creating a twelfth-century nuclear war or a thirteenth-century holocaust.
I think the most beneficial innovation that would have the least likelihood of backfiring (obviously no guarantees here) would be the concept of universal secular education. And I probably couldn’t resist introducing movable type as well. Then just sit back and watch things happen.
Yeah, but I’m unimpressed by their effort – with mirrors eah measuring about a foot square they get an overall focus several feet apart? That shows poor aiming. When they tried this in Greece back around 1970 (using mirrors each controlled by people) they were able to set fire to a boat from quite a distance back.
See this website for some info on this and on other successful re-creations:
Some folks here have suggested educating the populace and creating a police force. I’m not sure either of those would be in the best interest of the local rulers. Arming the populace is one of the worst things that could happen for a monarch, and if you need serfs to toil in the fields all day you don’t want them getting education-induced ideas in their heads. So you might run into a bit of resistance from the folks with the power.
Someone also suggested making standardized parts. That’s a great idea, but the reason standardized parts weren’t used before was because they were all hand-made.
I’ve read Frankowski’s books. The blatant sexism and pedophilia is a little scary, but the first book had some interesting ideas about our topic. The subsequent books didn’t; it was more along the lines of “I wanted an air force, so I invented planes.” How? No details.
I’ve thought about this subject a bit, and my area of expertise (systems administration) is completely useless in the 10th century. I think the biggest contribution I could make is in teaching algebra and trigonometry, if the local wise men don’t know it already.
The conditions offered in the OP are a bit unreasonable. The language I speak doesn’t even exist in the tenth century! I can probably struggle along, but convincing folks to let me teach them hygiene, and civil engineering is a stretch, when I have to spend most of my time trying to understand what folks are saying to me.
But let’s assume I can do it. It’s 900 something AD, and I have to choose a civilization I want to have become the dynamo of my new world order. Tough choice. I guess England. Simple hygiene first. Farming by crop rotation, education of children, literacy (Each one teach one model, at first.) Printing in successively more modern methods, sewage treatment, composting, and contour plowing, using moldboard plows, and horses. Gotta get folks to import sea salt, even if other salt is available. Oh, yeah, put up a really strong fortress at Thanet.
Import more horses, soon. Build schools of all levels, first chance. Send out bright young folks to learn from other countries what they are learning. Lens factory at Tintagel. Start encouraging small village militias, archery, and regular postal service. Encourage roads. Pony Express. Hygiene as a social duty, including dental hygiene from infancy. Banking, by the exchange of letters of credit, in lieu of specie.
Seek out the smartest tinkers and smiths. Design needle bearings, ball and race bearings, successively precise gear systems. Windmills, and hydraulic rams for water distribution. Large scale reservoirs and spill systems to eliminate drought. (Not hard to do in England.) Distributed manufacturing systems for textile industry, and shipbuilding. Subsidize jewelers, and metal workers. Navigation methods, using sextants, and a big push for clocks. Rose hip syrup. Trade trade trade. Military navy to protect trade. Regular quarantine of all animals and persons landing from foreign shores.
Iron. I don’t know much, but I know that coal heated in an oven becomes coke, and coke and iron ore in some proportion will give you pig iron. I know forced air furnaces get much hotter. Eventually, you can blow oxygen through it, and get steel, but I only know a little about that process. Gonna have to just make suggestions to the folks that are already working iron in this part of the world.
By this time, assuming I go right now, I am a very old man, so let’s assume I am not the time traveler, but rather some young man with a brilliant mind able to assimilate the same information I picked up in fifty five years. Even he is getting on in years. Best hope is to spend a lot of time dictating things for later generations. I can explain the methods that will give you the data of Tycho Brahe, and if I work at it, a whole lot, the basis of algebra, and trigonometry, from which calculus will give you the beginnings of the works of Kepler, and eventually Newton. Mostly, teach the scientific method, and logic of inference. Explain oxidation/reduction. Draw up as much of the Periodic Table as I can remember. Explain DNA, Genetics, and inheritance as areas of later interest, but beyond current technology. Explain the concept of logarithms, and set up the first efforts at four place tables for trig, and logs.
Explain civil defense, and guerilla warfare. Implant the concept of consent of the governed. Loyalty to the king is a duty parallel to the duty of the king to serve his people. Without that mutual duty, loyalty must be given to the people themselves.
At this point, you get hung.
Tris
England, 932 A.D.
Good choice. They’re still using coconuts.