“The medical authorities of the day had little to offer. ‘Leave quickly, go far and come back slowly’ was the general advice about what to do if an epidemic came to your town.”

How familiar does that quote sound to you?

It comes from the guidance of surviving a pandemic. It was when an unknown disease had spread from far away—no one could exactly pinpoint where, but they heard that it was Asia, for sure. It killed with precision and ease, and one of the best ways to avoid it was to practice quarantine. People attacked their neighbors and railed against the individuals in charge of their governments. The economy collapsed, and society completely changed as everyone knew it.

Although this may seem like a common beginning of yet another depressing COVID-19 article, this is about one of the most notorious plagues to ever wreak havoc on humanity. I’m talking about yersinia pestis, the Black Plague, the Great Death, that ravaged Eurasia through the 14th century, killing millions and lowering the population by as much as 60% in some countries in Europe (Austin Alchon, 2003). The science behind the Black Plague’s influence it is not only a good reminder of the precautions we are taking as a society, but also the influence that a horrifying disease can have on the social science of our species’ collective conscious, as well.  

A quick refresher for those who aren’t that familiar with this truly terrifying disease: once infected, an individual comes down with a fever, delirium, and severe fatigue, developing swellings in the armpits and groin that quickly turn black with infection. Sometimes, you barf up blood. Without modern hygiene and especially without antibiotics, you don’t stand much of a chance of surviving.

Black Plague (yersinia pestis) is a bacterium carried by infected fleas.
Black Plague (yersinia pestis) is a bacterium carried by infected fleas.

So, a bit of microbiology about this frightening illness. First, unlike SARS-CoV-2, the Black Plague is not a virus: yersinia pestis is a bacterium carried by infected fleas, which jump from host to host, mostly rats and humans, infecting them through a bite (Alberth, 2010). As this was an especially cramped time in Western history, with multiple populations becoming more urban in Europe as trade began picking up in the 14th century, it was a prime time for humans to live in uncomfortably close proximity to each other (Archaeologists focusing on architecture find evidence of this in the remains of houses found in places such as London and Florence.) With humans living close to each other, and creating huge trash piles, it was a perfect environment for rats to spread, including those carrying fleas who carried the bacterium that caused Black Plague.

Once a human is bitten, they could be inflicted with three types of plagues: bubonic (which is the famous one that caused black armpit swelling, fever, delirium, and a quick death, sometimes within days or even hours), pneumonic, where a victim’s lungs would basically collapse onto themselves, causing the victim to choke to death on their own blood, and finally, septicemic plague, which entered through the blood stream and attacked the cardiovascular system, which sometimes occurred as an evolved version of either the bubonic or pneumatic plague.

Although it killed millions of Europeans hundreds of years ago, it is rare to die of the Black Plague today. This is for a variety of reasons, chief of which being the advent of antibiotics—a bacterial disease of yersinia pestis type, when caught early, is dealt with quickly when exposed to modern medicine. Additionally, some archaeologists are now claiming that the spread of the Plague wasn’t caused by fleas jumping from rats to humans, but rather from infected human to infected human (Hufthammer and Walløe, 2012), so by avoiding other plague-ridden humans, you might arguably be safe from the disease. And then there are questions about our susceptibility to the bug, which has scientists are still debating to this day (Moneke et al, 2009). After all, the developed world is living a more hygienic life now, meaning we’re less exposed to vermin like fleas and rats that could infect us. That’s not to say everyone is protected: It still pops up in isolated areas around the world today.

Everyone, even those who are unlikely to get the plague in a million years, are still talking about it, from one of National Geographic’s recent issues to everyone on Twitter (props to Dr. Eleanor Janega, who corrects with misguided assumptions about the Black Plague, and was patient enough to talk about it with me). Why are we still talking about it, hundreds of years later? Because even though most of us aren’t at risk of catching the disease, its effects on society are still seen in our daily lives.

Fleas carry the bacterium and infect new hosts through a bite.

One of the things that shock many folks who take a medieval studies class (such as yours truly, who was a Medieval Studies major, thank you very much!) is how a population’s physiology can change after just one generation due to a massive pandemic such as the Black Plague. For the generation that survived that Black Plague, their children were found to have much longer lifespans (Schweich & Knüsel, 2003), as well as a much stockier, taller build. This could have something to do with the ample supply of food, given that there were fewer people around, and that those who were still around could purchase more. The medieval peasant had a lot more choices in life, which eventually did lead to some changes, such as the first true peasant revolt, Wat Tyler’s Rebellion (Basdeo, 2018).

But while the medieval peasant of the generation right after the Black Plague was arguably bigger, richer, and better fed, their society was not completely without multiple setbacks. This was especially true in places such as the lands that would eventually become Germany, which was brought to its knees by the Black Plague only a few years after one of the worst famines in European history (Jordan, 1997). The family unit fell apart at this time, as whole villages were wiped out, with only a few survivors straggling across an almost post-apocalyptic landscape. There was no one left to bury their dead, much less keep farms and villages going. For older individuals, especially older women, this meant there was no one to take care of them. As a result, many elderly women were abandoned in towns, fields, and even in the woods (Ben-Yehuda, 1980).

Think of the scary witches of many fairy tales, hiding in the woods. For some folklorists (and sociologists) this trope of abandoned, isolated old people in the woods can be attributed to the widespread heritage of the Black Plague, which existed in minds through our stories and collective psyche, rather than through just physical heritage. As we survive terrifying disasters, it isn’t just our bodies and health that evolve, but our mental health and fears as well.  

Witches aside, their holier counterparts were some of the hardest hit of all the victims of the Black Plague. At the time, many priests and nuns served in hospitals for plague victims and died from it. Subsequently, the Vatican felt the pressure to train more in order to replace their dead brothers and sisters of the cloth. This need to train such a large number of ecclesial members of society lead to a rise in scholarship in the form of the university (Courtenay, 1980). The Catholic church founded many of these schools to train new members of their various orders, ranging from the serving Vicentines (who would found Chicago’s DePaul University) to the intellectual Jesuits (who would found many of the medical universities that are still being used to train physicians today, such as nearby Loyola Medical Center in Maywood).

St. Charles Borromeo Giving Communion to the Plague-Stricken, drawing by Charles Le Brun.

Speaking of the devil, just like during our current pandemic, after the Black Plague had killed loved ones and strangers alike, many people during the middle ages were weary of death. The dead and dying no longer stoked fear and reminders of an impending doom from a vengeful God, but rather, it merely served as an ongoing occurrence that had battered, but not broken, them. Some scholars and scientists now credit this new line of thinking to the rise of the study of human anatomy and the rise of the surgeon, as described by David Herlihy in The Black Death and the Transformation of the West.

One of the deadliest outbreaks in our collective history produced some of the longest lasting changes to our cultural heritage. Surgeons, universities, folklore, and a somewhat stronger population would eventually help further Western society. 

I am not a traditional medieval scholar, and I am not an epidemiologist. But what I can say is that the effects of a plague are not only physical but sewn into the minds and psyches of survivors and their descendants. Although COVID-19 has ripped through and exposed the bones of the world, we have collectively learned, best of all, how to avoid disease, and that, perhaps, is our greatest gift from the Black Plague. We stay apart, we quarantine the sick, we keep infections to ourselves through masks (though not nearly as cool as a Plague Doctor mask), and we keep ourselves clean.


Schweich, M., & Knüsel, C. (2003). Bio-cultural effects in medieval populations. Economics & Human Biology1(3), 367-377.

Basdeo, S. (2018). The Life and Legend of a Rebel Leader: Wat Tyler. Pen and Sword.

Austin Alchon, Suzanne (2003). A pest in the land: new world epidemics in a global perspective. University of New Mexico Press.

Aberth, John (2010). From the Brink of the Apocalypse: Confronting Famine, War, Plague and Death in the Later Middle Ages(second ed.). Routledge

Hufthammer, Anne Karin and Walløe, Lars. 2012. Rats cannot have been intermediate hosts for Yersinia pestis during medieval plague epidemics in Northern Europe. Journal of Archaeological Science.

Monecke, S., Monecke, H., & Monecke, J. (2009). Modelling the black death. A historical case study and implications for the epidemiology of bubonic plague. International Journal of Medical Microbiology299(8), 582-593.

Courtenay, W. J. (1980). The effect of the Black Death on English higher education. Speculum55(4), 696-714.

Ben-Yehuda, N. (1980). The European witch craze of the 14th to 17th centuries: A sociologist’s perspective. American Journal of Sociology86(1), 1-31.

Jordan, W. C. (1997). The great famine: Northern Europe in the early fourteenth century. Princeton University Press.


Cultivated For Your Curious Self

Keep Your Learning Going

Did you enjoy this article? You’re our kind of person. And we think you’ll love these posts from our team of experts.

Total Solar Eclipse on April 8, 2024

Total Solar Eclipse on April 8, 2024

On April 8th, 2024, a total solar eclipse will sweep across North America, from Mexico to the Maine-Canadian border. For those who experienced the spectacular solar eclipse of 2017, this one will be similar, crossing the United States from west to east and passing through or near several major metropolitan areas. And while its path is quite different this time, Carbondale, Illinois, a reasonable destination for Chicago-area residents, will once again be on the line of totality.    

Just a little background on eclipses:  Lunar and solar eclipses are not uncommon – they each occur about twice a year when the moon is crossing the ecliptic, the path of the sun in the sky.

Two women representing the Illinois Science Council at an event.

Don’t Have the Time? Donate Today.

We know you’re busy. but you can still help. We’re an independent 501c3 nonprofit, and all donations go to bringing science to the community.

Donate Today