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In this setting, the Continent has been hit by several catastrophes, caused by the inner workings of planet's tectonics, and the eruption of a volcano far on the other side of the world. Gravest of them all, the great shroud arose, and the civilization, though not extinct, couldn't sustain highly organized states anymore, thus breaking down into poleis, villages and even solitary estates. This period will engrain itself in the collective consciusness, later being reffered to as the "13 Hells" (13 being the original number of days I intended it to last), and is the source of many superstitions, legends etc.

But - after some consideration, I began to doubt that an event, that lasted only 13 days, would leave such a significant mark in human history. Maybe I'm wrong; anyway, wanted to strech it a bit.

So my question is, what are the medieval civilization's limits to enduring the "Long night"?


  • The world, prior to the cataclism, is comparable to Europe's late Medieval Era.
  • There's no magic, nor any mythical beings nor properties.
  • The Sun isn't completely blocked.
  • If possible, the main cause of this darkness would be the eruption of aforementioned far away volcano, located east of the Continent.
  • During the period, the life in the mountains (in small, isolated villages) would still be possible, even if arduous. The villagers have good reasons not to descend, though these reasons are currently irrelevant.
  • For clarification, not all of humanity has gone up the mountains.
  • The mountain range, shown on the picture, peeks at an average of 5000 meters.
  • When "Long night" comes to an end, humanity should be able to slowly recover to its former glory.
  • If possible, the recovery should last for a couple of centuries.


  1. This event starts early in the year; late March probably.
  2. Catastrophies that occured immediately before "Long night" include earthquakes (which weren't highly destructive), and tsunamies (which hit southern and south-eastern coastal towns of the Continent and pretty much levelled them).

I appriciate all the help, cheers.

  • $\begingroup$ What time of year does this occur? That will highly influence its impact. Please modify your question to reflect your answer. $\endgroup$
    – kleer001
    Sep 16, 2019 at 20:08
  • $\begingroup$ Are you intending that people and plants should die to set-back population numbers a couple of centuries, or are you referring to religious uprising that provokes a second "dark ages" and retards scientific progress? $\endgroup$ Sep 16, 2019 at 20:11
  • $\begingroup$ @Measureofdespare. I'd say it's more of a second thing. $\endgroup$
    – scipio
    Sep 16, 2019 at 20:12
  • 2
    $\begingroup$ Tromsø is a city in Norway, situated at 69° northern latitude. It was established in the Middle Ages: the city was attested in the 13th century. From December 1 to January 10 the sun does not rise above the horizon. (That is 41 sunless days, and it happens year after year.) (And the essence of the western European medieval world was that society was pulverized into a mosaic of autonomous cities and autarkic villages and estates. No physical "long night" was needed -- the metaphorical long night induced by the collapse of the classical world was enough.) $\endgroup$
    – AlexP
    Sep 16, 2019 at 20:15
  • 1
    $\begingroup$ I don't see a volcano creating a 13 day event. After major volcanic eruptions it can take years for the climate to recover. I don't know of a natural effect that could turn darkness on and off in 13 days. Also, why do people in the mountains survive? What have they got going for them that other people don't? If anything, I would think the mountains would have it worse since they start off colder and with less of a heat blanket because of thinner air. Cold would likely be the biggest risk - a frost at the start of the growing season that kills crops and leads to starvation. $\endgroup$
    – Dan Hanson
    Sep 17, 2019 at 1:44

3 Answers 3


your description look exacly like krakatoa and tambora eruption.


The explosions hurled an estimated 11 cubic miles (45 cubic km) of debris into the atmosphere, darkening skies up to 275 miles (442 km) from the volcano. In the immediate vicinity, the dawn did not return for three days. Ash fell as far away as 3,775 miles (6,076 km) landing on ships to the northwest. Barographs around the globe documented that the shock waves in the atmosphere circled the planet at least seven times. Within 13 days, a layer of sulfur dioxide and other gases began to filter the amount of sunlight able to reach Earth. The atmospheric effects made for spectacular sunsets all over Europe and the United States. Average global temperatures were as much as 1.2 degrees cooler for the next five years.



and judging from this link seems like 13 days is enough to bring crop failure,malnutrition, famine, chaos, disease.

after all it surround entire world and new crop require time and the heavy rain probably undrinkable or to acidic for plant.

and Some historians even argue that the cool climate due to volcano eruption accelerated the collapse of the Roman Empire, leading Europe into chaotic times, with widespread migrations of peoples within or into Europe fleeing famine, diseases and war.

"And it came about during this year that a most dread portent took place. For the sun gave forth its light without brightness, like the moon, during this whole year, and it seemed exceedingly like the sun in eclipse, for the beams it shed were not clear nor such as it is accustomed to shed. And from the time when this thing happened men were free neither from war nor pestilence nor any other thing leading to death" - the Byzantine historian Procopius in 536 CE."


so volcano eruption may actually involve in creating dark ages civilization, not sure will medieval civilization will collapse since its a collapse civilization from the begining.

and there also a speculation about volcano eruption stronger than krakatoa during medieval, so seems like 13 days is not enough, but devastating enough i guess. but its a speculation after all.


the scream painting by Edvard Munich (it has nothing to do with the answer, i just want to add it because the painting is inspired by krakatoa eruption)

enter image description here

  • 2
    $\begingroup$ Thx, I'll opt for this as the best answer. Realized just now, the darkness doesn't actually have to last too long and besides, combining it with other catastrophies really decimates the population - but more importantly, social order. PS Great reference there, The Scream fits what I had in mind perfectly. PPS I found this article (theguardian.com/uk/2012/aug/05/…) as the most useful one. $\endgroup$
    – scipio
    Sep 17, 2019 at 15:35

13-days night won't destroy the civilization. But a multiyear winter may do that.

Medieval civilization did not have much dependency on trade or technology. Long night event may cause widespread panic and rioting, and ruling dynasties may be toppled - but so what? After day-night cycle returns to normal, so would the people. Burned houses would be rebuilt, lost crops would be reseeded, new kings will be crowned. Population losses, if any, would bounce back within a generation.

Medieval civilization, however, had strong dependency on food supply. It was just "getting by" in the years of regular crops, and showing obvious signs of strain when the crop yields were bad. What if we have several years without much crop at all? That would certainly spell trouble for typical medieval civilization. Kingdoms may break up for good, many people may die, and those staying alive may forget how to seed and reap.

One large sun-blocking event may result in "global winter", severely affecting the civilization. It may plunge into "dark ages", while the pre-calamity days would be remembered as "golden age".

  • $\begingroup$ So, maybe hit a few critical months when the crops are still growing. That would leave people without yield (or it being late), the following year. Also, the changes in weather would be felt throughout several years, still affecting the crops' growth. Seems like a good start, anyway. Thx $\endgroup$
    – scipio
    Sep 16, 2019 at 22:32
  • 1
    $\begingroup$ @scipio - Disrupting one year's growing season would be bad, but it would be so much worse if it was following an already bad year (which happened often enough, I think, not to be out of place). Especially if the event (and aftermath) also dealt a lot of damage to the wild ecosystems folk traditionally leaned on when their own crops didn't come through. Winter to winter with no reserves would be hard. If they were already running thin from a bad year, or the consequences echoed into next year's growth, that would be much worse. With a bit of (bad) luck, well, there goes your civilization. $\endgroup$
    – Megha
    Sep 23, 2019 at 1:28

To use an overused term, "Technically" forever. We need light in the short term due to our overuse of it. Most of any population would die off after a few years due to all forms of organic resources becoming less available. We don't rely one hundred percent on sunlight to live, mainly to stay healthy we need sunlight. A stable food source would be the main concern, although after several years most of the staple plant & animal life will have died off there would still be alternative forms of foodstuffs, like fish & Fungi. We could "technically" live on in darkness as long as we adapted to survive on these food sources. I doubt scratching around in the dark eating fungi would be much fun though.


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