It began on a sweltering July day in 1518, in the city of Strasbourg, then part of the Holy Roman Empire. A lone woman, known to history as Frau Troffea, stepped out of her home and began to dance. There was no music, no celebration. She simply danced, her body jerking and twisting in the street. Her silent, feverish performance continued for hours, until she collapsed from exhaustion, only to resume her frantic movements after a brief rest.

By the end of the week, she had been joined by over thirty others. Within a month, the number of dancers had swelled to a staggering 400. This was not a festival; it was a living nightmare. The Dancing Plague of 1518 had begun.

The Fever Spreads

As Frau Troffea’s strange compulsion proved contagious, the city’s elite grew alarmed. Physicians were consulted, but they were as baffled as everyone else. Ignoring supernatural explanations, they diagnosed the affliction as “hot blood” – a natural disease caused by an overheated temperament. Their prescribed cure was as bizarre as the illness itself: the afflicted must dance the fever out.

Following this medical advice, the city authorities took a disastrous step. They cleared open-air markets, erected a large wooden stage for the dancers, and even hired professional musicians to provide a steady beat. The intention was to encourage non-stop dancing, believing it would burn off the excess “heat.” Instead of a cure, their actions created a macabre spectacle. The relentless music only seemed to fuel the frenzy, drawing in more suggestible onlookers who were soon swept up in the mania.

The scene was terrifying. Hundreds of men, women, and children danced uncontrollably through the streets of Strasbourg. They were not dancing with joy; their faces were contorted in agony and desperation. They pleaded for help but could not stop moving. The physical toll was immense. Day after day, a continuous public rave with no escape, they danced until their feet were bloody and their bones were sore. Many collapsed and died from sheer exhaustion, heart attacks, and strokes. At its peak, the plague was said to claim as many as 15 lives per day.

From Mania to Penance

When it became gruesomely clear that the “more dancing” cure was a fatal failure, the city council changed its approach. Panic and superstition took over. The authorities now believed the plague was a divine curse, a punishment from God. The dancing was attributed to the wrath of Saint Vitus, a Christian martyr who, according to popular belief, could inflict a dancing curse upon sinners.

Public spectacles were banned. The stage was dismantled, and the musicians were sent away. In a desperate act of penance, the remaining dancers were gathered and taken by wagon to a shrine dedicated to St. Vitus, nestled in the nearby Vosges Mountains. There, they were made to pray for absolution. Historical records suggest that after this religious intervention, the epidemic began to wane, and the dancing slowly petered out by early September.

Unraveling the Mystery: The Leading Theories

For centuries, the Dancing Plague of 1518 has been a chilling historical puzzle. How could hundreds of people be compelled to dance themselves to death? While a definitive answer remains elusive, modern historians and scientists have proposed several compelling theories.

Theory 1: The Poisonous Fungus (Ergotism)

One of the most popular early theories suggested the dancers were victims of ergotism. Ergot is a mold that grows on damp rye, a staple grain in the 16th century. Ingesting ergot-tainted flour can cause a condition known as St. Anthony’s Fire, which has two variations: gangrenous (restricting blood flow to extremities) and convulsive.

The convulsive form leads to painful muscle spasms, seizures, and hallucinations. Since the active ingredient in ergot is lysergic acid—from which LSD is derived—it’s plausible that the dancers were experiencing a mass drug-induced trip. The region around Strasbourg was prone to famines and grain shortages, making the consumption of diseased rye a real possibility.

However, most historians now doubt this theory. While ergot can cause convulsions, the symptoms don’t quite match the coordinated, sustained dancing described in historical accounts. Furthermore, ergot poisoning typically incapacitates its victims or restricts blood flow, making it highly unlikely that hundreds of people could dance for days on end. It is also improbable that such a large group would have the exact same rare reaction to the poison.

Theory 2: A Plague of the Mind (Mass Psychogenic Illness)

The most widely accepted explanation today is mass psychogenic illness, often called mass hysteria. This phenomenon occurs when a group of people, under extreme psychological distress, begin to exhibit similar physical symptoms for which there is no known physical cause. It is, in essence, a psychiatric epidemic spread by sight and suggestion.

The context of Strasbourg in 1518 makes this theory incredibly compelling. The populace was suffering under what historian John Waller calls a “perfect storm” of misery:

• Famine and Poverty: A series of harsh winters, crop failures, and soaring grain prices had led to widespread starvation.
• Disease: The city was ravaged by deadly diseases like smallpox, syphilis, and leprosy. Death was a constant, visible presence.
• Superstition and Stress: The people were deeply religious and superstitious. They genuinely believed in the power of saints to both heal and curse. The fear of divine wrath was palpable.

In this crucible of stress and despair, it is believed that people entered a trance-like state. Dancing manias, while rare, were a known cultural phenomenon in the region, often linked to the curse of St. Vitus. Frau Troffea’s initial dance may have acted as a trigger. For a populace on the brink, seeing one person succumb to this known “curse” could have been enough to tip others into the same dissociative state. The authorities’ intervention—building a stage and hiring musicians—only legitimized the event and amplified the contagion.

A Haunting Echo in History

The Dancing Plague of 1518 stands as a chilling testament to the profound connection between the mind and body. While the image of people dancing to their deaths is bizarre, the underlying causes—extreme stress, pervasive fear, and social contagion—are timeless. The event was not a whimsical festival but a desperate, collective cry of a community pushed past its breaking point.

We may never know with absolute certainty what drove Frau Troffea to dance that fateful July day. But her story, and the terrifying craze it unleashed, serves as a haunting reminder of a time when the lines between medicine, faith, and fear were dangerously blurred, and the human mind itself became the source of a deadly plague.