In the summer of 1518, a bizarre and inexplicable event unfolded on the streets of Strasbourg, a city then part of the Holy Roman Empire. It began with a single woman, known as Frau Troffea, who suddenly and inexplicably started dancing in the streets. There was no music, no apparent reason, and, crucially, no way for her to stop. Within days, dozens of others had joined her, their bodies convulsing in an unrelenting and frantic rhythm. By the end of the month, the number had swelled to hundreds, and many were collapsing from exhaustion, suffering broken bones, or, according to some reports, even perishing from strokes or heart attacks. The phenomenon became known as the Dancing Plague of 1518, one of history’s most perplexing and chilling mass hysteria events.
Authorities were at a loss to explain the cause of this strange affliction, and their response only exacerbated the situation. Instead of attempting to halt the dancing, they encouraged it, believing that the victims would only recover if they danced the affliction out of their systems. Musicians were hired, and public halls were opened, transforming the streets into an eerie, unrelenting carnival of uncontrollable movement. But rather than alleviating the problem, this approach only seemed to intensify the suffering. More and more people fell into a relentless, involuntary rhythm, their feet bruised and bleeding, their bodies tormented by exhaustion and pain. Some collapsed from sheer fatigue, while others reportedly succumbed to heart failure after hours or days of ceaseless motion.
Theories about the cause of the Dancing Plague have abounded over the centuries, though no definitive explanation has been reached. Some historians and medical experts believe that the dancers suffered from ergot poisoning, a condition brought on by the consumption of rye contaminated with a hallucinogenic mould. Ergot poisoning can cause muscle spasms, hallucinations, and a sensation akin to burning limbs, which might account for some of the dancers’ distress. However, while ergotism has been implicated in various historical phenomena, it does not entirely explain the frenzied and coordinated dancing observed in Strasbourg. Unlike the hallucinations and gangrene often associated with ergot poisoning, the afflicted individuals in Strasbourg appeared to be caught in a state of trance-like compulsion, which was neither entirely conscious nor wholly unconscious.
Another theory suggests that the event was an extreme case of mass hysteria, now known as mass psychogenic illness. This condition arises in situations of extreme psychological distress, often manifesting in physical symptoms with no clear organic cause. At the time, the people of Strasbourg were under enormous strain. Famine, disease, and economic hardship loomed over the city, and many were deeply superstitious, believing in divine punishment and supernatural afflictions. The psychological burden of these crises could have triggered a collective breakdown, manifesting physically in the form of uncontrollable dancing. In this context, it is possible that Frau Troffea’s initial dance triggered a psychological chain reaction, spreading among an already vulnerable population through collective anxiety and fear.
There is also speculation that the Dancing Plague was linked to religious fervour. Medieval Europe was a deeply devout place, and some have suggested that the dancers were engaging in a form of involuntary religious ecstasy. Certain accounts suggest that they were calling upon Saint Vitus, a Christian martyr believed to have the power to curse people with compulsive dancing. Some of the dancers reportedly made pilgrimages to a shrine dedicated to Saint Vitus, after which their affliction seemed to ease, lending some weight to the idea that the event was tied to religious and cultural beliefs. During the Middle Ages, there were various reports of so-called “dancing manias” linked to saints and religious rituals, further suggesting that the Strasbourg outbreak may not have been an isolated event, but rather part of a broader pattern of mass psychological or spiritual phenomena.
Adding to the mystery, the Dancing Plague was not the first recorded outbreak of such an affliction, nor was it the last. Similar incidents had been recorded as early as the seventh century and continued sporadically into the seventeenth century. Reports from Germany, France, and the Netherlands document entire communities seized by uncontrollable movement, often accompanied by singing, screaming, and strange bodily contortions. Some historians link these outbreaks to the concept of choreomania—a term used to describe compulsive, frenzied dancing episodes throughout history.
By autumn of 1518, the Strasbourg epidemic gradually subsided. Whether through sheer exhaustion, death, or a shift in public perception, the afflicted individuals eventually ceased their convulsions, and the phenomenon faded from public life. Though efforts were made to understand the event at the time, no conclusive answers emerged, and the Dancing Plague of 1518 was left to posterity as one of history’s most perplexing enigmas.
Modern psychologists and historians continue to study the Dancing Plague as an example of the profound effects of stress, belief, and environment on human behaviour. It remains one of the most well-documented cases of mass hysteria, providing insight into the ways collective trauma and social pressures can manifest in unexpected and dramatic ways. Some researchers have drawn parallels between the Dancing Plague and more recent outbreaks of mass psychogenic illness, where groups of people exhibit shared, inexplicable physical symptoms without a clear medical cause. This suggests that while the circumstances of 1518 were unique, the underlying mechanisms behind such events may still be relevant today.
Ultimately, the mystery of the Dancing Plague endures because it defies easy categorisation. Whether it was driven by hallucinogenic poisoning, psychological distress, religious fervour, or a combination of factors, the image of hundreds of people dancing uncontrollably in the streets of Strasbourg remains one of history’s most unsettling enigmas. It is a testament to the fragile nature of the human mind and body, and a reminder that sometimes, history presents us with events that resist simple explanations. The Dancing Plague serves as both a cautionary tale and a fascinating case study in the complexities of collective human behaviour.
