The Dancing Plague of 1518

Summary

In July 1518 a woman began to dance in a Strasbourg street, without music and apparently without wanting to. She could not stop. Within a week dozens had joined her. Within a month there were hundreds, and some of them were dying of it.

This is not a legend. It is recorded in physicians' notes, in municipal orders, in cathedral sermons and in regional chronicles. Something happened. What is disputed is why.

What is documented

The first dancer. In July 1518, a woman recorded as Frau Troffea stepped into a street in Strasbourg and began to dance. She had no music. She danced until she collapsed, rested, and began again. Four of the six surviving chronicle accounts name her; the others describe an unnamed woman.

The spread. Within about a week, more than thirty others were dancing. Over the following weeks the number grew. Estimates in the sources range from around fifty to around four hundred. They danced past exhaustion and past injury.

The deaths. Contemporary accounts describe deaths from exhaustion, stroke and heart failure. The number is disputed; some sources report as many as fifteen deaths a day at the peak, and that figure is not securely established. That people died is well attested. How many is not.

The response, which is the strangest documented part. The city authorities did not disperse the dancers or treat them as possessed. They concluded, on the medical theory of the day, that the affliction was caused by overheated blood and that the cure was to dance it out. So they helped.

They cleared a space at the horse market and in the guildhalls. They hired musicians. They brought in professional dancers to keep the afflicted moving. The city, acting on its best medical advice, organised the epidemic.

It did not work. When it became clear that the dancers were dying, the policy was reversed: the music stopped, dancing was banned, and the afflicted were taken to a shrine of Saint Vitus in the hills.

The end. It subsided in September, about two months after it began.

The precedent. Strasbourg 1518 is the best-documented case, not the only one. Outbreaks of compulsive dancing are recorded across the Rhine and the Low Countries over several centuries. They form a genre, and the genre matters, because any explanation has to account for more than one city.

Leading explanations

Mass psychogenic illness (leading). The dominant modern account, argued in detail by the medical historian John Waller. It requires two things, and Strasbourg in 1518 had both.

The first is extreme, prolonged stress. The region had been through repeated famine. Disease was widespread, including smallpox and syphilis. The city was under severe strain, and had been for years.

The second is a shared belief that gives the illness its shape. Mass psychogenic outbreaks do not take arbitrary forms; they take the form the culture supplies. In the upper Rhine, people believed that Saint Vitus could afflict sinners with uncontrollable dancing. The belief was specific, it was widely held, and it was available.

Waller's argument is that under sufficient stress, in a population that believed dancing sickness was a real and impending punishment, the belief became the symptom. And crucially, the authorities' response then poured petrol on it: by hiring musicians and clearing dance floors, the city publicly confirmed that the affliction was real, was spreading, and was happening to people like you.

Ergotism (weak). Rye infected with the ergot fungus produces alkaloids that can cause convulsions and hallucinations, and ergotamine is chemically related to LSD. This is the popular explanation and it has serious problems.

Waller's objections, made in The Lancet, are that people poisoned by ergot could not plausibly have danced continuously for days, and that so many people would not have reacted to a psychotropic compound in the same specific way. Ergotism also constricts blood flow to the extremities, and its hallmark is gangrene: blackened limbs. The Strasbourg accounts do not report it. And rye was not a staple everywhere that dancing outbreaks occurred, which the theory has to explain and does not.

Ergotism produces convulsions and rigidity. It does not produce sustained, fluid, purposeful-looking dancing for days on end.

A heretical sect. Robert Bartholomew has argued the dancers were members of a religious sect, dancing to attract divine favour, and were not afflicted at all. It accounts for the persistence but not for the terror in the sources, or for the fact that the dancers and their families sought a cure.

Demonic possession, and overheated blood. The two explanations available in 1518. The registry records them because they determined the response, and the response made it worse.

Current status

Partially explained. That the event occurred is not in doubt. That it was a mass psychogenic episode, shaped by the specific local belief in Saint Vitus and triggered by sustained collective stress, is the leading and best-argued explanation. It cannot be demonstrated, because the evidence required to demonstrate it died in 1518.

The registry keeps this record for one detail above all the others. The most consequential decision in the whole affair was made by the city council, acting in good faith, on the best medical advice available to them, and it was the worst possible decision. They built a stage.

Last reviewed: July 2026. Records are provisional. Where the evidence changes, the entry changes. Found an error? Tell us.