The Plague the Doctors Prescribed
In July 1518, a woman in Strasbourg started dancing in the street and would not stop. Within a month hundreds of her neighbors had joined her, some dying where they fell — and the city's own doctors had ordered it.
On the fourteenth of July, 1518, a woman the records call Frau Troffea walked out into a narrow street in Strasbourg and began to dance. There was no music. There was no festival, no wedding, no reason anyone standing nearby could name. She simply moved, and kept moving, for what accounts describe as hours, until her body gave out and she collapsed in the dirt.
Then, having rested, she got back up and did it again.
She danced through that night and into the next day, and the day after that. Her feet split open. Neighbors who came to watch could not get her to stop, could not get her to explain herself, could not get her to so much as acknowledge them. By the time anyone with authority in the city took real notice, she had reportedly been at it for the better part of a week, on feet that no longer looked like feet.
What makes Frau Troffea more than a strange footnote in a strange century is what happened next. She did not stay the only one. Within about a week, something like three dozen other residents of Strasbourg had taken up dancing in the same compulsive, apparently involuntary way — in the streets, in the market square, wherever the impulse found them. By the end of that month, according to the accounts historians rely on, the number of afflicted dancers had swelled toward the hundreds. Modern historians who have combed the surviving record — physicians’ notes, cathedral sermon references, civic and regional chronicles — generally agree on this much: something happened in Strasbourg that summer, in public, to a very large number of people, and it does not fit easily into any category we have ready for it. As the medical historian John Waller, who has written the most extensive modern study of the episode, puts it: that the event took place is not seriously disputed. What caused it is where everyone starts arguing.
A city already under strain
Strasbourg in 1518 was not a happy place to begin with. The region had just come through a string of poor harvests, and famine was biting; grain was scarce and expensive, and the people dancing themselves into collapse were, by most accounts, the same people who had spent the preceding months hungry. Smallpox and syphilis — the latter a relatively new and terrifying arrival in Europe at the time — were both circulating. And the religious world was cracking open: Martin Luther had posted his theses the previous year, and the anxieties of an empire about to split its church were already in the air, even if no one in Strasbourg that July could have named what was coming. None of this proves anything by itself about why people danced. But it is the air everyone in this story was breathing, and most of the historians who study the event treat it as essential context rather than coincidence.
There was also a very specific piece of folklore hanging over the region: a legend that a vengeful Saint Vitus, a martyr from the fourth century, could curse people with an uncontrollable urge to dance if they angered him. “Dancing mania,” or choreomania, was not a brand-new phenomenon invented in Strasbourg. Historians who study the wider pattern trace it back centuries earlier: a group of peasants reportedly disrupted a Christmas Eve service with compulsive singing and dancing in Bernburg, Germany, in the 1020s; a crowd of children is said to have danced from Erfurt to Arnstadt in 1237, in a story later compared to the Pied Piper legend; and in 1238, roughly two hundred people are reported to have danced on a bridge over the Meuse until the bridge itself collapsed under them. The best-documented of the earlier outbreaks began on June 24, 1374, in Aachen, when crowds began dancing uncontrollably in front of a church altar; the mania spread to other cities along the Rhine and reportedly peaked at some 500 participants in Cologne before subsiding months later. These episodes tended to cluster around the same conditions Strasbourg would see nearly a century and a half afterward — crop failure, famine, and the kind of generalized dread that followed the Black Death across Europe — and they were consistently explained the same way, as a curse that a wronged saint had sent down on the afflicted. Strasbourg’s 1518 episode is simply the best documented of all of them, because by then the city kept unusually thorough records, and because this time, uniquely, the authorities’ own response to the crisis made everything worse.
The cure that was the disease
Faced with a growing crowd of people who could not stop moving, Strasbourg’s city council did what any city council of the period would do: it turned to physicians for a diagnosis.
The doctors examined the dancers and concluded that the cause was physiological — an excess of what they called “hot blood,” a feverish imbalance that needed to be worked out of the body rather than suppressed. Their prescribed treatment, accordingly, was more dancing. Let the fever burn itself out. Encourage it, even.
The city council took this medical advice seriously enough to act on it at civic scale. Officials cleared space — accounts point to the grain market — built a wooden stage, and hired musicians: drummers, pipers, players to keep a beat going around the clock. They are also said to have brought in professional dancers, paid to dance alongside the afflicted, on the theory that this would help burn through whatever was consuming them, faster and more completely.
It did not work. If anything, giving the phenomenon a stage, a soundtrack, and an audience seems to have fed it. More people kept joining. The dancing didn’t taper off under official encouragement — it intensified, and the human cost climbed with it. Contemporary and near-contemporary accounts describe dancers dying where they fell, from strokes, from heart attacks, from sheer physical exhaustion after days without real rest. Some sources describing the episode’s worst stretch put the toll at as many as fifteen deaths a day at its peak. The precise total who died, as opposed to the total who were afflicted, is one of the points where the surviving records simply run out — different accounts give different numbers, and nobody today can reconstruct an exact body count from documents written five centuries ago by people who were themselves overwhelmed and frightened. What isn’t in serious dispute is that people did die, in public, while dancing, and that the city’s prescribed remedy had been, in effect, to make sure they kept doing it.
Giving up on music
At some point — the record doesn’t preserve the exact moment anyone changed their mind — Strasbourg’s authorities abandoned the dance-it-out strategy entirely and swung to the opposite extreme. They banned public dancing and music outright. And instead of trying to treat the affliction as a medical fever to be worked through, they reclassified it as what the old folklore had always said it was: a curse, specifically the wrath of Saint Vitus, requiring not musicians but penance.
Dancers were loaded onto carts and taken on a pilgrimage to a shrine dedicated to the saint, in the town the records call Zabern — known today as Saverne, roughly thirty miles from Strasbourg. There, according to the accounts, they prayed, underwent rites associated with the saint’s shrine, and were, in the eyes of the people who brought them, cured. By late summer or early autumn of 1518, several weeks after Frau Troffea first stepped into that street, the dancing had stopped. Strasbourg, as far as the surviving record shows, never saw anything like it again at that scale.
Why it happened, and the argument that still isn’t settled
Five hundred years on, the question that resists an answer is not whether this happened — the documentary trail, while imperfect, is unusually strong for an event this old — but why.
The explanation that circulates most widely in popular retellings is ergot poisoning: a theory that the dancers had unknowingly eaten rye bread contaminated with a fungus that produces compounds related to LSD, causing hallucinations and involuntary spasms. It’s a tidy explanation, and it’s the one many general audiences have heard. It is also the explanation that John Waller, whose work is the most detailed modern treatment of the episode, argues against most forcefully. Ergot poisoning, he points out, typically works by constricting blood flow to the extremities — producing burning pain, blackened and gangrenous limbs, and in severe cases a slow, agonizing death, not days of sustained, coordinated, full-body dancing. None of the surviving accounts of the Strasbourg dancers describe gangrene or blackened limbs. And ergotism tends to strike people idiosyncratically, based on who happened to eat the bad grain; it does not readily explain why dozens and then hundreds of people would converge on the identical symptom of continuous dancing, rather than the scattered, varied convulsions and hallucinations ergotism usually produces.
Waller’s own explanation is psychological: a stress-induced trance state, triggered in a population that was already starving, frightened of disease, anxious about religious upheaval, and — crucially — primed by generations of folklore to believe that uncontrollable dancing was a real and specific curse that a vengeful saint could and would inflict on them. In communities that believe such a thing is possible, he argues, extreme psychological distress can produce exactly this kind of involuntary, trance-like episode, and it can spread from person to person as others watch, absorb the belief that this is what’s happening to them, and fall into the same state themselves. On this reading, the musicians and the dance floor Strasbourg built didn’t cause new cases out of nothing — they gave a susceptible, terrified population a stage and a permission structure to do, publicly and in large numbers, what their culture already told them this curse looked like.
Not every historian who has studied the episode signs on to Waller’s account in full. Some researchers place more emphasis on the dancing as a form of ritualized religious behavior — a communal response to crisis that borrowed the shape of worship and pilgrimage, rather than a purely involuntary psychiatric event. The disagreement matters less for the purposes of this story than what both sides agree on: the explanation is not simple, a fungus in the bread is probably not sufficient on its own, and whatever was happening to the people of Strasbourg that summer was bound up tightly with what they already believed could happen to them.
What’s left
No one alive today can interview Frau Troffea, or ask the Strasbourg city council what it was thinking when it hired a drum circle to treat a medical crisis. What’s left is the paper trail — physicians’ notes, chronicle entries, the kind of incidental civic record-keeping that happens to survive for five hundred years by accident rather than design — and the strange, almost darkly comic shape of the response it documents: a city that looked at a public health crisis, correctly recognized it needed a cure, and then spent weeks administering the thing that was actually killing people, in the sincere belief that it was medicine.
The dancing stopped, eventually, once Strasbourg stopped prescribing it and started praying instead. Whether the saint deserves the credit, or whether removing the music and the crowd and the civic sanction was itself the actual treatment — taking away the stage that let a shared panic keep feeding itself — is a question the city’s own records were never going to be able to answer, and modern historians still argue about it five centuries later. What nobody argues about is that for about a month in the summer of 1518, in a city already strained by hunger and disease and the first tremors of a continent’s religious rupture, people danced until it killed some of them, and the authorities whose job was to stop it spent weeks making sure they didn’t.