In 1518, hundreds of people in France danced uncontrollably for weeks until they collapsed; historians still cannot solve this mystery

The summer of 1518 brought one of the strangest events ever recorded in European history. In the city of Strasbourg, France, then part of the Holy Roman Empire, a woman stepped into the street and began dancing. There was no celebration, no music, and no clear reason. Yet she continued for days. Soon, others joined her. Within weeks, hundreds of people were dancing without being able to stop.

More than 500 years later, historians and medical researchers are still debating what exactly caused the mysterious outbreak, often referred to as the Dancing Plague of 1518 or choreomania. While several theories have been proposed over the centuries, there is still no single explanation that everyone agrees on.

How the dancing plague began

According to History.com, the episode began in July 1518 when a woman named Frau Troffea stepped into a street in Strasbourg and started dancing without any apparent reason.


As historian Evan Andrews wrote in History, "In July 1518, residents of the city of Strasbourg (then part of the Holy Roman Empire) were struck by a sudden and seemingly uncontrollable urge to dance. The hysteria kicked off when a woman known as Frau Troffea stepped into the street and began to silently twist, twirl and shake."

Historical accounts say she continued dancing for nearly a week. Soon, dozens of others joined her. Within about a month, reports suggest the number of dancers had climbed to around 400.

The city authorities, believing the condition had a physical cause, made a decision that only worsened the situation. A stage was built, musicians were hired and even professional dancers were brought in because physicians believed the sufferers needed to keep dancing until the illness passed. Instead, many participants collapsed from extreme exhaustion, while some reportedly died from heart attacks or strokes.

What people believed at the time

Medical knowledge in the early 16th century was limited, and religious beliefs shaped how people understood unusual events.

Doctors reportedly blamed the condition on "hot blood," while many residents believed the dancers had been cursed by St. Vitus, a Catholic saint who was associated with uncontrollable movement disorders. The afflicted were eventually taken to a shrine dedicated to St. Vitus in the hope that prayers and religious rituals would end the outbreak.

An article published by the Edinburgh University Press Journals includes a poem from contemporary chronicles describing the terrifying scenes: "Many hundreds in Strassburg [sic] began, To dance and hop, women and men, In the public market, in alleys and streets, Day and night; and many of them ate nothing. Until at last the sickness left them. This affliction was called St Vitus' dance."

The poem reflects not only the scale of the outbreak but also how people at the time viewed it as something connected to divine punishment rather than medicine.

Why modern historians disagree

Researchers have spent decades trying to understand what really happened.

One theory suggested the dancers had eaten rye contaminated with ergot, a toxic fungus that can cause hallucinations and muscle spasms. However, many historians believe this explanation does not fully fit the evidence because ergot poisoning usually causes severe pain and muscle contractions that would make prolonged dancing extremely difficult.

Today, many scholars favour the idea of mass psychogenic illness, sometimes called mass hysteria. A study published in Frontiers of Neurology and Neuroscience points to the conditions in Strasbourg at the time. The city had been hit by repeated crop failures, famine, disease, poverty and widespread religious fear. Researchers suggest that intense psychological stress may have spread through the community and taken physical form.

Historian John Waller, quoted by History, argues that "When combined with the horrors of disease and famine, both of which were tearing through Strasbourg in 1518, the St. Vitus superstition may have triggered a stress-induced hysteria that took hold of much of the city."

A mystery that continues to fascinate

The Strasbourg outbreak was not the only documented case of choreomania in Europe, but it remains the best recorded. Similar incidents were reported in parts of Germany, Switzerland and the Netherlands between the Middle Ages and the early modern period.

Experts also caution against looking at the event only through a modern medical lens. As per National Geographic, historian Lynneth Miller Renberg said researchers should also consider the religious beliefs and cultural context of the time rather than focusing only on finding a medical diagnosis.

Even after five centuries, the Dancing Plague of 1518 remains one of history's most puzzling episodes. Whether it was driven by psychological trauma, religious belief, environmental factors or a combination of several causes, there is still no definitive answer to explain why hundreds of people danced until they collapsed.