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In the near future time I invent time travel. But when perfecting it, something goes wrong and I'm transported back to the time and place of the Black Death. I wasn't prepared for this, and try as I might, I can't find my time machine (those parts could've been useful), so I'm stuck here for a while at least. I didn't bring anything except the clothes on my back (luckily I have a penchant for wearing medieval clothing at all times, so retro ...). And I sure am lucky I learned a few thousand living and dead languages while in school, so I'll be all right wherever I am or go.

I have to figure out some way to survive without modern medicine and hygiene. People are already dying around me, and it's possible I've already caught it, so there's little time to try to reestablish any kind of modern technology.

Some of what I could try to do is probably obvious - good nutrition/hydration, isolation, surrounding myself with cats to kill the rats, makeshift facemasks, wash with soap, boil water, get some citrus and see if I can make some rudimentary penicillin.

Are these things going to be feasible? Are there any other things I can do? What are going to be my biggest challenges achieving these things? What skills can I be recognised for quickly to use to trade for some of these things? Am I going to get burnt at the stake for my strange ways?

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Comments are not for extended discussion; this conversation has been moved to chat. – Serban Tanasa Mar 19 at 22:00
Forget citrus--that's for the rich. At least in temperate regions, and until our parents were children. – Mathieu K. Mar 20 at 4:22

13 Answers 13

up vote 69 down vote accepted

If you have European blood in you, are aged between 19 and 45 and are physically fit, the chances of you being brought down by the plague would be very little. Read this Scientific American article for details.

Also this livescience article states that the pandemic altered the genes of European people. The Europeans who survived the plague developed immunity to it. If you have White (European, specially of the regions directly hit by the plague) blood in you, it is more than likely that you carry natural immunity to the disease.

On the other hand, if you are not a white person, the chance of you getting infected by black death is 1/3. Isolation, prayer and karma are your best hopes. Try to move out of the masses and settle in a cabin in the woods. And make sure to repent for all your sins and misdoings while you are alive and healthy, for you would not get the time if the demons of black death spot you ...

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White blood? Oh no, I'm out of luck, my blood is red... – theonlygusti Mar 15 at 12:15
@theonlygusti white blood cells are for immunity. – Andrew Grimm Mar 15 at 12:19
* facepalm* ... white blood as in => Caucasian blood. – Youstay Igo Mar 15 at 12:36
@YoustayIgo , people in other parts of the world also suffered from the plague. I'm not certain about how devastating it was in those other regions though. People of Northern European descent didn't develop immunity to the disease, people are still getting bubonic plague even today. However, their bodies are able to mount a much more effective defense against it now. – Jim2B Mar 15 at 14:43
You might want to change that "white blood" to "European ancestry". All humans have natural genetic variation, which produces varying degrees of immunity to different diseases. If you're descended from Europeans, you're descended from people who either never caught the plague or didn't die from it, so you're likely to have natural resistance. See e.g. "virgin field epidemic" for more details. Beyond that, use modern hygene, fleabane, and keep a cat or two to kill the rats. – jamesqf Mar 15 at 18:50

There are three forms of the plague, bubonic (famously from fleas), septicemic (as much from other infected people, like those with bubonic plague) and pneumonic (also from other infected people).

If you're going to catch the plague, catch bubonic plague, the others will kill you within 24/36 hours respectively. With bubonic plague you actually have a reasonable chance of survival.

  • Don't surround yourself with animals at all, cats also get fleas. Have a general policy of avoiding all animals.
  • Keep your living area clean and clear.
  • Hard surfaces only. It was normal to have a rushes on the floor, rats and fleas love this, get tiles or slate floor, invent concrete if you have to. Keep it clean.
  • Avoid infected people It's hard to emphasise this enough. Infected people are a higher risk to you than fleas.

If there's nothing for the rats to live on, you won't get rats. Remember that hard alcohol is a good disinfectant.

There's a lot more about the plague over on

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Concrete had been invented long before the Black Death. :) – Charles Mar 15 at 13:31
@Charles, invented then lost and forgotten again – Separatrix Mar 15 at 13:42
@AndreiROM, not everyone was a farmer, plague outbreaks tended to be in urban areas anyway. No supermarkets, but markets did exist for what you needed to buy. – Separatrix Mar 15 at 13:47
+1, RE: "Avoid Infected People", in particular avoid any human or animal that has recently died or is about to die. When any mammal carrying the infected fleas dies (for whatever reason), the fleas will immediately leave the body seeking any warm living mammals in the area. This is by far the most dangerous time and the most likely point when the disease gets spread. – RBarryYoung Mar 15 at 17:40
@JanDvorak, candles are a prohibitively expensive luxury at that point in history. Even in the 19th Century (200 years later) a family with two servants (i.e. not poor) would still only use one candle in an evening, and you want to wax the floor?! :) Tar is the sealant of the period but it gets sticky at quite low temperatures (melts @ 55-60degC) – Separatrix Mar 17 at 8:43

Convince everybody the plague is spread by rats.

You know what causes the plague. It's caused by fleas carried by infected rodents, or by inhaling pathogens exhaled by infected individuals. The most effective way you have of surviving the plague is making sure that everybody else in the world knows this as well. Try to convince them that you have authentic knowledge, either from some far off group of people or indirectly from god. (Claiming direct divine contact could get you killed.) Tell them that a dying monk gained this revelation and told you to share it with everybody, and that it's the only way to live. Be creative.

If everyone else knows what causes the plague, you can begin to enact public health measures around it. Quarantine infected people, ensure all caretakers and doctors have some sort of filter mask and gloves, enforce sterile conditions for plague sufferers, and work to remove as many potential breeding grounds for rats as possible.

You can also quarantine any travelers for a few days before they enter towns, again doing so in a sterile area which you can ensure is rat-free. This worked well for Poland, which had one of the lowest rates of plague death in Europe.

Most importantly, start killing the rats and cleaning up cities. Medieval cities were filthy places, which contributed to many diseases including and beyond the plague. If you can convince the city dwellers that hygiene and sanitation are important things, you'll significantly improve the lives of everybody.

Lastly, if you convince everybody that fleas borne by rats cause the plague, and significantly reduce plague deaths as a result, you stand a good chance at being able to tell them what causes other common but deadly diseases, as well. Typhus is caused by lice, cholera and typhoid spread through water and food exposed to fecal bacteria, and smallpox is spread by assholes with blankets. Avoid those things and society should be far better off.

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+1 for the blankets... sensible, shameless chuckle – corsiKa Mar 15 at 21:03
Don't forget - stop everyone from persecuting cats. More cats = less rats = less rat fleas. – Monty Wild Mar 15 at 22:21
It's worth noting that this could require some hand waving if you want to prevent heavy modification of the future. Huge swaths of people who did die suddenly survive? That could cause heavy consequences. – Sam Weaver Mar 16 at 11:30
Can I still spread smallpox with a towel? I was told that having a towel is the most important item that I can carry. – The Anathema Mar 16 at 16:51
"Tell everyone"? In an age before the Internet, television, radio, newspapers, widespread literacy...? I suspect that only nation states and the Church had sufficient apparatus to disseminate information rapidly and widely—and even then, "rapidly" would be measured in the order of many months, perhaps even years. Nevertheless, suppose one somehow manages to convince the King, or the Pope, or some other sufficiently influential person to embark upon a project of notifying the masses—I find it highly unlikely that the masses will take sufficient notice of the advice they eventually receive. – eggyal Mar 17 at 20:19

Go to Poland, Milan or the Basque region.

enter image description here

This is the map of the spread of the Black Death according to Wikipedia. As you can see, these 3 regions are just about the only areas that the plague wasn't as widespread. There were also some minor villages in alpine regions that had less infections, but those are harder to find and get to.

The only concern is whether you are useful enough to risk bringing in a plague carrier. Since you say you know many older languages, you might be able to make yourself useful as a translator for a nobleman or even a king.

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And then he brings the plague there himself, and changes the future by infecting these regions himself... typical :-o – Falco Mar 15 at 13:47
Central Poland was isolated and inaccessible. In Milan they sealed the house and burned it with everyone inside if anyone living there got the plague. – Separatrix Mar 15 at 13:49
@Falco changing the future is out of scope for the purposes of this question. For all intents and purposes, I treat any question on WB involving time travel as happening in a multiverse theory. – Nzall Mar 15 at 15:03
"As usual, not corrupting the rest of history is left as an exercise to the reader." – corsiKa Mar 15 at 19:08
Normally, I just assume that it is impossible to alter the past. Any actions you take simply put you back where you started. Strange dude with a scar tries to kill you, so you go back in time and try to kill him. You fail, and he ends up with a scar... – XandarTheZenon Mar 16 at 4:01

There's a vaccine, get vaccinated:

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A perfect answer to the letter of the question. Not so much the spirit of the question, but oh well! – CAgrippa Mar 15 at 22:00
I'm not 100% sure whether a modern vaccine is all that suited for a 700 year old illness. I mean, we need to recreate our flu vaccine every year. – Nzall Mar 16 at 15:56
@NateKerkhofs The flu is a special case due to it's rapid mutation. – Loren Pechtel Mar 16 at 23:50
Might want to get a whole slew of vaccines before you go, actually. There's a lot of nasty stuff that we've cleaned up in the past 700 years. – corsiKa Mar 17 at 14:32
Given the first two or three sentences establish this was an accident and no preparation was done (yes I know I really should have prepared ...), it doesn't answer the letter of the question either. If you know it's going to happen, you could take an entire portable "hospital" with antibiotics and whatever else, long-term food & water supplies, spare parts or just avoid the accident entirely. The possibilities are many with access to modern tech. – matty Mar 18 at 4:41

It is believed that the primary vector of the Black Death was a flea bite. If that is true, you could reduce your vulnerability by heavy ingestion of apple cider vinegar, a natural flea repellent.

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This is marvelous! Could you provide some reference? – Ciacciu Mar 15 at 10:59
@Ciacciu under garlic and yeast which supposedly are also natural flea repellents. No reference is given. It is specified "unpasteurized" so it is probably some volatile aromatic compounds that make your blood taste awful to fleas that are important here. Yeast might be the easiest of the natural repellents to get a large supply as you can grow it fast. You really want everyone else around you to have less fleas as well. So feeding yeast to even animals (including rats) might be a good idea. – Ville Niemi Mar 15 at 12:35
Although, IIRC some animals die if you feed them yeast, so maybe just humans, rats, dogs, and cats. – Ville Niemi Mar 15 at 12:40
@Ciacciu, references added. – Henry Taylor Mar 15 at 13:57
Another thing from the article I linked above worth mentioning is fresh water diatomaceous earth. if character knows geology and is in an area with a deposit it is worth digging up. You probably won't have resources to prepare it in any particular way, but even in its natural form it is dangerous to most pests and nearly harmless to mammals and plants so you can spread it around everywhere and kill lots of fleas (and other pests). – Ville Niemi Mar 15 at 14:01

In medieval Europe, you can significantly reduce your risks without drawing attention to yourself if you are careful. Fleas are generally quite close to the ground so wearing long boots will give you more protection then anything else. Gloves, hats and long sleeved jackets will all improve your protection without looking outlandish and can be traded for or stolen locally.

Skills that you could bring with you (without being accused of witchcraft) to trade for your requirements are a much harder problem then I thought they would be. Tanning and hardening leather would give you a quick return but exposes you to carcasses and would make it very hard to maintain hygiene. On the other hand, it would get you used to medieval hygiene standards before you got there. Tool making could be very useful.

There is an advantage to keeping all your hair short or clean shaved but make sure to sterilize any blades you come in contact with. Water is a problem, more so in towns or cities, so try to drink beer or wine instead if you are forced to visit them (for markets etc.). Wash all food before preparing it and only eat food you have prepared. This makes visits to 'civilisation' all the more difficult.

Your challenge will be to stay healthy. One dose of the runs will weaken your immunity and expose you to everything else going. Stay clear of crowds and corpses, human and animal.

A good write up of the effects of the Black Death exists in the 'Baroque Cycle' by Neal Stephenson, though it covers a later period around 1665.

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+1 for simple sensible precautions. Everyone jumped to grand solutions, but I think it's good to point out the simple things one wants to do even if they can't pull off killing every rat in the world. – dsollen Mar 17 at 20:21
? IIRC, the Baroque Cycle talked a little about smallpox (with one small part in which it became significant) and a little about syphillis. No plague at all. – SJuan76 Mar 20 at 21:16
Plague is mentioned directly at least twice in the 1st book. The first time at the Cambridge market when Issac is buying a lens, the second when Daniel walks into London to retrieve papers and scientific knick-knacks (which is when the boots are mentioned). – Paul Smith Mar 21 at 10:00

Here are some practical steps you can take to reduce the risk of infection:

  • Boil your water and cook your food thoroughly - sanitation was virtually non existent in medieval Europe and that could lead to infection.
  • Avoid fleas. Fleas can be killed with high temperature so build a sauna. Wash your clothes in boiling water with soap. Bathe regularly. You can also use salt and baking soda to kill fleas. Finally you can try to produce bleach and use it as disinfectant.
  • Avoid infected people. Insist everyone you come in contact follows the procedures outlined above. Wear face mask.

If you are in a position of power (you are from the future after all), you can also enforce sanitation norms (rat & flea eradication, proper disposal of corpses, quarantine the sick, etc) and thus reduce the infection rate in your city.

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Yeah. Understanding the germ theory of disease gives you a huge unfair advantage over all your (literally) unwashed medieval companions. – Ollie Jones Mar 15 at 23:15
Is cooking everything likely to lead to any deficiencies over the course of the plague? Perhaps implicit in this is trying to get my fruit off the tree and so on. – matty Mar 18 at 5:23
How can I build a sauna? Sounds quite difficult in medieval times. – matty Mar 18 at 5:24
The question sets up a situation where I have just arrived and have to deal with the situation quickly, so I am unlikely to be in a position of power (unless I can somehow be quickly worshipped due to my futuristic skills, but that's risky business as mentioned elsewhere). – matty Mar 18 at 5:26
@matty The reason for cooking everything is to kill any bacteria that's in the water / meat. You don't have to cook fruits and veggies but you will have to wash them very well. Saunas are very easy to build. It's just a small room with a large pile of hot coals. You can easily raise to power - just say you know how to save the city from the plague. – ventsyv Mar 18 at 17:14

Survivors of the plague produce copious amounts of antibodies in their serum, which can be used as a treatment mechanism.

In fact, an article in the International Journal of Epidemiology mentions the technique being used in 1900 (first described in this The Lancet article) to treat plague sufferers in India.

The data showed a recovery rate more than double of the untreated control group, when edge cases were isolated:

|                | No.  | Died  | Recovered  | % mortality  | % recovery |
| Serum cases    | 313  |  189  |       124  | 60.38        | 39.62      |
| Control cases  | 297  |  237  |        60  | 79.79        | 20.21      |

Of course, you must ensure that you are considered a proper doctor by the populace, otherwise you are likely to be burnt at the stake for drawing blood from survivors and fractionating serum from it.

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Not likely to be punished that way. Blood-drawing was normal. Nobody has to see you fractionate serum from it. As to injections, there are more than enough techniques around that one more isn't going to seem all that odd -- and if it works, you're all set. Now getting accepted as a doctor might seem a problem, but if you just want to draw blood, you can set up as a barber easily enough, or even hire out as a cheap leech. – CAgrippa Mar 15 at 21:58
Sadly, double the recovery rate is only 3/4ths the mortality rate in this case... – ErikE Mar 18 at 1:03
How do I obtain sufficient equipment to draw blood? I wouldn't have thought it was easy to transfuse blood in medieval times. And how do I deal with blood types? Personally I don't know my blood type ... – matty Mar 18 at 5:13

The plague is a bacterial disease meaning that it is susceptible to antibiotic treatment. If you were fortunate enough to be carrying antibiotics with you at the time they might save you. Of course you have already mentioned that this is not an option.

Another method which has actually been used during the time of the black death by one high ranking city official was placing himself in a ring of fire that his subordinates kept burning while the plague swept through the city. This way no rats or fleas could get to him and transmit the deadly disease.

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Just make sure to bring a guitar and a Johnny Cash songbook. – papirtiger Mar 15 at 11:33
What if it rained on your ring of fire? – March Ho Mar 15 at 11:40
Use something that is hard to put out like oil – Jaywalker Mar 15 at 11:41
The ring of fire suggestion isn't entirely accurate to reality. The guy was actually Pope Clement VI, and the one who suggested the idea was Guy de Chauliac. Guy was a physician/surgeon. According to these articles, the suggestion actually wasn't a full ring of fire, but instead to keep a fire burning (or some torches; the two articles disagree) in his chamber and keep everyone else out. But supposedly, he got skeptical about the fire and ditched the idea. – Devsman Mar 15 at 12:44
Remember how salt was quite expensive? They used a lot of it per capita (food storage) but also it was a lot more economical to transport it from somewhere it could be naturally evaporated or mined rather than boil seawater (look up surströmming) In other words, fuel took up a large part of your expenses. Ergo if you were nevertheless going to do something silly like that, it wouldn't be cheap, and you would need to buy the loyalty of enough bodyguards that the destitute mobs aren't tempted to reward your conspicuous consumption by tossing you in with the firewood. – Paul Milovanov Mar 17 at 12:16

Ride a horse. A horse gets you off the ground and out of the range of fleas, and fleas don't like horses for some reason.

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Fleas do not like horses? Dream of it! – Hohmannfan Mar 18 at 0:41
Horse fleas do not carry the plague. This is a stupid idea that may really work :D People will think you're crazy, but probably less than if you insist having a shower every week. – Madlozoz Mar 18 at 9:28
@Madlozoz They won't think you're crazy if you tell them your legs don't work. I suspect they had disabled people back then. – Pharap Mar 18 at 10:02
There are ways other than fleas that you can get infected. Drinking contaminated water is one. – ventsyv Mar 18 at 17:51

As mentionned earlier, the best way is to be an healthy western european adult.
I also hope you were wearing some valuable jewelery as poverty is the meanest killer around

Other important things:


Forget generic hygenic rule for a minute and focus on FLEAS (mostly from rats, secondary from human). Most likely, the only guilty flea at this time was Xenopsylla cheopis.
You can not (easilly) avoid occasional flee byte, but you can avoid to have them permanently dwelling on you.
- Wash you clothes daily. Doesn't matter if it is filthy cold water. Flees drown easily, period.
- Wash you body twice a day. As a naked monkey, you only need a sponge and a bucket.
Those 2 rules are the reason we don't usually have fleas nowadays despite those still beeing around everywhere.

Somebody sugested high leather boots. Sound sensible, but awfully expensive.

Generic hygiena

Somehow, you landed in a world where bacteria and viruses evolved 700 years backward. Most likely, you immune system will not reconize any of those.

So, chances are you will die of a bad cold or gut infection.
Or smallpox. I can't recomand to much reading
And if those don't immediatly kill you, they will make you weak enough to become a potential target for Yersinia pestis.

Boil your water, wash your hand before you eat and... well... avoid human if possible. Or try to meet them outdoor (UV is not germs best friends)

healthy food

Easier said than done.
Whole wheat bread (cheap) and fruit (expensive off season) plus a bit of protein (don't be picky; just avoid dead rats) is what you need. Wheat bread is enough protein for basic survival.

Guess what: commoner were not having bad diet by choice.
If you don't have a source of income, even bread is expensive.

And remember: This is pre-columbus world. Most beans (protein source) aren't available in Europa. You will find peas, mostly in winter.


Somebody sugested to avoid ANY animal. This is nonsense.
Yersinia pestis is a bacteria specific to a few species of fleas. And while not being totally specific, thoses flea prefer rodents.
And rodent hate cats.
More specifically, modern rats and mices are know to be repelled by cat urin. Cats pee where they live, so have cats living with you. Problem is we can't be 100% sure this behaviour was already true in late middle age.
Oh! And feed him well as you don't want him to bring dead rats at home

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If you feed him well, doesn't that negate the whole rat-killing thing? And as many modern cat-owners can tell you, sometimes they bring them home anyway ... :) – matty Mar 18 at 9:03
Even a starved cat will not hunt all the rats. The goal is to scare them away. Having a cat bringing dead rats home is a concern. Maybe you should lock him. – Madlozoz Mar 18 at 9:24
Healthy foods - nonsense. The plague affected rich and poor alike, never heard of anyone avoiding bacterial infection due to eating healthy. Immune system won't recognize it - nonsense. The plague hit Constantinople in 541 and again in 1347 and it still infects people today. There is no reason to expect that someone from the 20th century will be immune to it. – ventsyv Mar 18 at 17:45
@ventsyv (1) Eating unhealthily generally weakens your immune system and opens you up for infections. Eating healthy is definitely a big factor in overall disease avoidance. Wealthy ≠ healthy eating, which is why poor and rich alike were affected by the plague. (2) This answer made the point that bacteria and viruses except for the plague differ between today and 1300. This is very true, and actually a huge concern (correctly noted in this answer). Plague is a special case and the opposite, because (descendants of ) Europan plague survivors are genetically better equipped against the plague. – Konrad Rudolph Mar 20 at 21:33

When the monks were taking care of the plague victims throughout Europe, God Herself came down and gave them a recipe. Saidest She:

"Taketh thou equal parts white onion, garlic, horseradish root, ginger, and habanero pepper, and mince finely. Then thou shall pour over a hearty apple cider vinegar until the mince becomes well submerged. Settest thou mince aside for a fortnight. Protection from the plague will be upon whoever shall ingesteth this concoction in copious amounts daily."

That's exactly what She said.

If you make a lot of this (e.g., use a pound of each), it will last you several weeks, and you may be able to find your time machine. And no, you can't substitute jalapeno for the habs.

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And where doth God propose one finds these ingredients? Habanero peppers come from Mexico, which would make them incredibly hard to get hold of and very expensive. Garlic likewise comes from the east (notably China and India) and would also be reasonably hard to get hold of for a peasant. Working in the spice trade might be a solution, but even then you'd have to be sure the company was trading with the right places, and borders of other countries would be locked off to avoid plague contact. – Pharap Mar 18 at 10:15
@Pharap ...and, in the 1300s there wasn't any habanero pepper in Europa, Colombus's voyage happened at 1492... – Morning Star Mar 18 at 14:32
@Pharap: garlic was already popular in ancient Rome and probably feasible to obtain in medieval Europe (of course not imported from China but locally grown). Ginger would be much harder to get your hands on, and Habanero indeed simply impossible. Anyway, it would just be much cleverer to ditch those spices and use the vinegar to repel the fleas, and I reckon the OP is well aware of this. – leftaroundabout Mar 18 at 23:11
@leftaroundabout I think I got garlic and ginger mixed up when writing my comment. – Pharap Mar 19 at 0:01
@MorningStar That I did not know. I decided to opt on the side of logistics rather than date checking – Pharap Mar 19 at 0:03

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