In the middle of July 1518 — the chronicles put it at the 14th or the 22nd — a woman known to them only as Frau Troffea walked out of her half-timbered house onto a narrow Strasbourg lane and began to dance. There was no music. There was no festival. She moved with a strange, jerking insistence, her arms thrashing, her face slack, and she kept moving as the morning wore into afternoon and the afternoon into evening. When she finally dropped from exhaustion, she slept where she fell, and then she rose and danced again. By the time she had been at it for several days, blood was seeping into her shoes.
Her neighbors did not laugh for long. Within a week, more than thirty of them were dancing too.
A city already on its knees
Strasbourg in 1518 was a place that had run out of luck. The free imperial city, then part of the Holy Roman Empire in Alsace, had come through a stretch of brutal years: failed harvests had driven up the price of grain, the poor were starving in the streets, and the diseases of the age — plague, smallpox, and the new and terrifying arrival of syphilis — moved freely through a malnourished population. The hospitals were full. The almshouses were full. People were primed for the conviction that God, or one of his saints, was angry.
That conviction had a specific shape. Across the Rhineland there was an old and durable belief in Saint Vitus, a martyr who, the faithful held, could afflict those who offended him with a compulsion to dance. It was not an abstract fear. People in the region genuinely believed that Vitus could seize the body and force it to move until it broke. So when bodies in Strasbourg began moving exactly that way, the explanation was already sitting in everyone’s head.
The contagion spreads
The dancing did not stay with Frau Troffea. It jumped — from one person to the next, day after day, through the heat of a Rhineland summer. Within roughly a month, according to a family chronicle kept by the Imlins, as many as four hundred people had been pulled into it.
They were not dancing in any ordinary sense. Witnesses described convulsive, involuntary movement: people drenched in sweat, eyes vacant, feet swollen and bleeding, screaming for help even as their limbs refused to stop. This was not joy. It looked far more like torment performed as dance. And the longer it went on, the more dangerous it became — the bodies were simply giving out. Some accounts, drawn largely from later reconstructions, hold that at the height of it as many as fifteen people were dying each day from stroke, heart failure, and sheer exhaustion. The contemporary city records that survive do not actually tally the dead, so the true toll is unknown; what the documents do show is a city government that had clearly decided it was facing a lethal emergency.
A diagnosis of overheated blood
The authorities turned the problem over to physicians, and the physicians applied the medicine of their century. The reigning framework was the theory of the four humors, in which illness came from an imbalance of the body’s fluids. The dancers, the doctors concluded, were suffering from “hot blood” — an overheating of the body that had to be worked out of the system. By the ordinary rules of humoral medicine, that called for bleeding them. The physicians reached instead for the remedy that had been used on past sufferers of this same bizarre affliction.
If the affliction was overheated blood that needed to burn off, then the cure was not to stop the dancing. It was to finish it.
So the city committed itself, with municipal seriousness, to the most counterintuitive public-health program imaginable. Guild halls were cleared and turned into dance floors. Open-air wooden stages were thrown up in the grain market and the horse market. The council paid for musicians — pipers, drummers, fiddlers, horn players — to keep a beat going, and it brought in healthy, hired dancers to move among the afflicted and keep them upright and going. The theory was that constant motion, supported and sustained, would exhaust the sickness out of them.
It did the opposite. Music and crowds and the spectacle of public dancing only drew more people in. The thing fed on exactly the conditions the city had built for it.
The retreat to the saint
When it became obvious the cure was making the disease worse, Strasbourg reversed course completely. The stages were pulled down. Dancing and music were banned in public — drums and tambourines outlawed outright, strings permitted only at private weddings. And the city fell back on the explanation it had probably half-believed all along.
The worst-afflicted were loaded up and carried out of the city to a shrine of Saint Vitus in the hills near Saverne, some thirty miles away. There, priests led them through a rite of appeasement: the dancers were set before a wooden image of the saint, given small crosses and red shoes, sprinkled with holy water, their feet marked with crosses of consecrated oil. Whether the ritual healed anything or the outbreak had simply run its natural course, the dancing began to ebb. By early September 1518, it was over.
What was it?
For centuries the obvious modern explanation was poison. The favored candidate was ergot, a fungus that grows on damp rye and contains compounds related to LSD; eat enough contaminated bread and you can suffer convulsions and hallucinations. The trouble, as the medical historian John Waller has argued, is that ergot poisoning constricts blood flow to the limbs — it is associated with gangrene, with arms and legs blackening and dying. A body in the grip of ergotism could not coordinate days of sustained dancing. The chemistry and the symptoms do not match.
Waller’s own account, now the most widely accepted, reads the episode as one of the most extreme recorded cases of mass psychogenic illness — a disorder of the mind expressed through the body, spreading by suggestion through a population under unbearable stress. The ingredients were all present in Strasbourg in 1518: famine, disease, and a fervent, specific belief that a saint could make you dance against your will. In a community already at the edge, Waller argues, that belief became a kind of self-fulfilling trance, one suggestible body triggering the next. The historical record offers a cleaner parallel than any laboratory could: in 1962, a fit of uncontrollable laughter broke out among schoolgirls in Tanganyika and spread from village to village for months, closing schools, with no toxin ever found.
The dancers of Strasbourg were not faking and were not, in any simple sense, mad. They were ordinary, frightened, hungry people whose dread found a single shared channel and poured into it — until four hundred of them were dancing in the streets, and the only authorities they had decided the way out was to play them a faster tune.