Suppose you are going on a trip back to 1300 Western Europe. You can take supplies with you and a contingent of people to help run things.

You can only travel once and your goal is to stay for the rest of your lives.

  • You may bring some high technology items like solar panels, but only a few.
  • You may bring some consumables (ammunition, gas) but in limited quantities and with the understanding that you are likely to run out at some point.
  • You are limited to roughly 20 people you can bring back, but assume you are able to impress upon locals as you arrive and so you will have a source of labor for construction.
  • Assume that high-ticket/high-tech items will detract from your total amount of goods taken back by a large amount (i.e. everything has a cost, and the more advanced good you bring back, the less of everything you can take).
    • E.g., taking back a laptop filled with information, schematics, calendars, historical events -- along with solar panels or generators to keep it running -- will cost a lot and mean you can only bring back a few other items/materials.
    • This goes for people brought back as well. Scientists, linguists, engineers all come with 'cost'.
  • Do not forget you are mortal.
  • You'll likely need some good linguists because the locals aren't likely to understand you.
  • You will meet stiff opposition from everyone, as you'll be seen as some sort of tyrannical mage/warlock. Assume you will have to defend your position continually. Crusades will be launched against you.
  • You can choose a general area to land, but the exact location will be random (up to a hundred miles away).

I am hesitant to define how much you can bring back, but let's say you have up to an acre of raw space to transport back for everything (materials, people, etc).

What do you bring back? And what is your gameplan?

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    $\begingroup$ Q: Why should taking back an iPhone sized computer with a few hundred gigabytes worth of thumb drives cost me more than taking back a 200lb bodyguard? I can recharge the iphone with bicycle and a palm-sized generator, like you use for a bicycle headlamp. It sounds to me like you just don't want the obvious taken back. An iphone has a minute fraction of the connections in a human brain, which is far more informationally complex. Your restrictions don't make sense; your time machine is not discriminating based on either mass or informational complexity; just your whim. $\endgroup$ – Amadeus-Reinstate-Monica May 21 '17 at 22:36
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    $\begingroup$ Think of it as the difficulty in creating things different from substance at the time-target. An axe exists both in this time and in history, so it's 'cheap' to travel. A computer is a very particular arrangement of materials and data that does not have an analog in history. Guns and bullets are closer (the components exist, but they differ in form enough to still have a cost). Metals and raw material exist on both ends. Think of cost as a function of what would go in to recreating from raw material. An iPhone requires rare metals, specifically processed silicon, etc. $\endgroup$ – Mike Manfrin May 21 '17 at 23:51
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    $\begingroup$ And of course some of this is plain whim, we're talking about a hypothetical teleportation back in time. A certain amount of arbitration is needed. $\endgroup$ – Mike Manfrin May 21 '17 at 23:52
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    $\begingroup$ Good luck with your question. If I were reading this story, I would put the book down, no longer able to suspend my disbelief. Matter is matter, teleportation of a human brain would require atomic level precision, the iPhone features are gigantic in comparison to the inner structure of a single neuron. To me this is a deus ex machina, and an "explanation" that makes no sense. You'd be better off with MORE restrictions; like no metal larger than a pinpoint can be transported. $\endgroup$ – Amadeus-Reinstate-Monica May 22 '17 at 0:34
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    $\begingroup$ can i just take Elon Musk, Hawking and some Engineers and have them decide what we need? $\endgroup$ – Olaf Klausson May 22 '17 at 5:16

In light of my above comments; I would transport about a library full of schematics, science, physics, chemistry, medicine, biology and history, history, history: of every valuable patent, how important biological and chemical discoveries were first made -- especially things like explosives, cures, refining metals, etc. I would transport this microscopically printed on very fine paper, and with it, many binocular microscopes for reading. I believe I can easily get 400 book pages per sheet (20x reduction for both length and width), front and back.

I would bring support personnel, both to protect me, and to provide engineering services: The venture would be a partnership in the aim of getting rich. For a lifetime we would be pre-empting every important invention of the age by years; and in particular inventions we knew caught on like wildfire.

We would exploit every major political or natural event. Strike gold and find treasure where we knew others found it, years before they had any notion of looking where they eventually found it, in History 1.0. In History 2.0, we find it first. We invent it first. We discover it first. We put forth the new ideas first. We know when the earthquakes and floods are coming, we know when the monarchs are weak and can be overthrown, we know their weaknesses. We know where to explore the unknown.

Once we take over the world, we can establish a benevolent socialist Democracy like Norway and change the lives of billions for the better.

Added: As for building a castle: We don't need to, but eventually, we can get our followers to do it for us. Instead of a belligerent attitude, I can arrive as a savior and saint, sent by God to save lives, end hunger, diseases, slavery and subjugation. We will take protective weapons and personnel; martial artists skilled in medieval weaponry and fighting. It is a harder road to save lives instead of ending them, and end suffering instead of causing it, but every person you save puts a dozen more on your side, and that will snowball until they abandon their despotic kings and come to you in droves, begging to join the team.

Save them, organize them into a collective force that defends each other, and you and your team by extension. Introduce sanitation, education, dentistry, anesthetics (and surgery), basic nutrition, the French Method in farming! Use modern knowledge to grow food, stay healthy, and recruit others. Then if you still want a castle, the people that love you will happily build you ten.

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The secret to establishing a medieval sanctum, as with most major ventures, is planning and preparation. The OP has established that time-transport costs are closely linked to how difficult each item is to replicate from scratch in the target age. So these travel costs can be minimized (and the quantities transported maximized) through careful adherence to the following protocols...

  • Transcribe all information onto the medium of the day (parchment and ink). Leave your i-phones and laptops in the present.
  • Prefabricate your castle by carving all of the fitted stone using modern mill-works to precisely replicate 12th century hand chiseled stone. Similarly, cast all of your castle's iron works out of target-age appropriate raw iron, but use modern forges to maximize the quality and minimize the total expense.
  • Assemble your castle on the acre launch pad using modern forklifts and cranes then remove those motorized tools from the acre because they are not coming.
  • Select your fellow travelers not only for their technical skills, but also for their multilingual fluency in English, French, German and Italian. Yes, they will have to adapt for almost a thousand years of lingual drift, but having everyone multilingual is probably a stronger starting point than having a couple of dedicated linguists.
  • While you are at it, include some martial arts requirements in your staff selection process. Everyone should have at least one black belt or its equivalent in an ancient weapons technique.
  • Provision your castle with large quantities of the best heritage fruits and vegetables seeds for your targeted region, along with multiple mating pairs of appropriate livestock, burden beasts and horses. Choose your animals from bloodlines which have proven histories of hardiness and disease resistance. It doesn't matter that your selected plants or animals aren't native to your target region, as long as they existed somewhere on the planet during your target time.

In selecting your target region, the most important issue is not encroaching on the lands of other well-established castle owners or armies. Either choose a date prior to an area's initial settlement, or directly after a devastating plague. Or choose a place where castles were never built in the first place. Since you are bringing your own pre-assembled castle with you, choosing an area which lacks the necessary stone resources will give you a major advantage over your neighbors.

Now with all of the basics covered at an absolute minimum cost in anachronism, it is time to open the metaphorical wallet and give ourselves a few modern luxuries (in order of importance)...

  • Antibiotics, vitamins, sterile medical supplies
  • Well-drilling equipment and multiple manual well-heads
  • Hardened steel swords and plow blades
  • Indoor plumbing preinstalled in the castle with piping for a septic field
  • Modern Fertilizer
  • Survivalists (Bear Grylls-types)
  • Scientists (medical doctors, botanists, engineers, historians)
  • Geared windmills for grinding grain, drilling wells and pumping water
  • Spring steel for catapult and ballista construction
  • Packets of modern beer, mead and wine brewing yeasts
  • Modern acoustic instruments
  • An alcohol still
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Geographical maps showing where important resources are located, precious metals and useful ores. A good doctor or two and maybe a chemist with enough knowledge to make useful medicines, disinfectants etc,. out of plants, and make explosives out of raw materials, a few practical engineers able to smelt ores, repair and manufacture, make cannons or similar, and a bunch of fully equipped experienced soldiers and a couple of tanks.

How would you build a castle?

You wouldn't, you'd just go take someone else's and move in, terrorise the countryside into supplying you with food, women, and resources such as labour at first and live as comfortably as you can while training your nearby villagers youngsters for whatever you need them to do in the future.

You don't need the full sum of future knowledge, this is plenty to make you ruler of all you survey. You can generate your own electricity using water power or something and manufacture everything you need for the next 50 years of your life and beyond. More important to have the firepower to take what you need at the beginning and protect it.

Long term it's better to have the engineers who can make the tools from scratch than to have the tools themselves.

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  • $\begingroup$ If you own the castle you own the land and the people around it $\endgroup$ – Separatrix May 22 '17 at 10:44

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