A physician wearing a 17th-century plague prevention costume

Death on the doorstep

The Black Death was the most severe pandemic ever recorded

In 1348 the Black Death swept through Europe. It is estimated to have killed at least 75 million people, which probably makes it the most devastating pandemic in human history.

Its cause and origins have been debated for a long time. While some have argued it was caused by the bacterium Yersinia pestis, responsible for the bubonic plague that hit Europe in the 19th century, others say it had the hallmarks of a viral infection. In 2010 an international team of researchers published the results of DNA analyses that they claim show “unambiguously” that Y. pestis caused the Black Death.

Eyewitness accounts give us an idea how devastating the disease was: “Villages and hamlets became desolate, not a house being left in them, all having died who dwelt there.” It spared neither the young nor old: “I observe about me dying throngs of both young and old, and nowhere is there a refuge.”

It was so infectious that “in whatever household it took hold, whosoever took care of the sick, all the carers died of the same illness”. It was so virulent that “almost nobody survived beyond the fourth day”.

There was no treatment, “neither doctors nor medicine proving of any vail”. And the aftermath was bleak. “There were also those who were so sparsely covered with earth that the dogs dragged them forth and devoured many bodies throughout the city.”

Some credit the Black Death with causing a profound social shift in England. After it subsided, labour was scarce, so the remaining serfs found themselves with far more power – landowners were now competing for their services. So the peasants that survived became a little more prosperous. And they also became more mobile, for the first time moving around the country for work.

Three plague pandemics

The Black Death was the world’s second pandemic. The Plague of Justinian of 541–42 CE is the first recorded. Named after the Eastern Roman Emperor Justinian I, it killed between 30 and 50 million people – around half of the world’s population. It is thought to have been a factor in the downfall of the Roman Empire.

The ‘Third Pandemic’ began in China in 1855. It went on to kill around 10 million people. Plague remains a threat in some parts of Asia, and there are fears that global warming may increase the risk of new outbreaks by encouraging the spread of bacteria-infected fleas and the great gerbils they live on.

Lead image:

A physician wearing a 17th-century plague prevention costume.

Wellcome Library, London CC BY


Further reading

About this resource

This resource was first published in ‘Epidemics’ in September 2007 and reviewed and updated in January 2015.

Microbiology, Health, infection and disease, Medicine, Immunology
Education levels:
16–19, Continuing professional development