The Dancing Plague of 1518: When an Entire Town Danced for Weeks

A Woman Started Dancing and Could Not Stop

In mid-July 1518, a woman named Frau Troffea stepped into a narrow street in Strasbourg — then part of the Holy Roman Empire — and began to dance. She danced without music, without apparent joy, and without stopping. Within a week, approximately 34 people had joined her. Within a month, the number had grown to around 400 participants, many of whom were dancing until they collapsed from exhaustion, injury, or heart failure. Contemporary accounts, including records from physicians, town magistrates, and the Bishop of Strasbourg, document the episode in unusual detail for the period. The Dancing Plague of 1518 remains one of the most extensively recorded and most puzzling mass behavioral events in European history.

The Documentary Record

The historical evidence is stronger than for most medieval anomalies. Surviving sources include medical records, notes by physicians appointed by the Strasbourg city council, correspondence from the region's imperial governing body, and a chronicle by the humanist physician Paracelsus, who visited Strasbourg around this time.

The Strasbourg city council's written response is particularly telling. Magistrates initially believed the dancers needed to keep moving to recover — a standard medieval medical theory based on humoral medicine suggesting the affliction resulted from "hot blood." Acting on physician advice, the council opened guild halls and hired musicians to accompany the dancers, and brought in additional performers to maintain the dancing. They also cleared public spaces. This likely worsened the outbreak significantly by normalizing the behavior and creating a supportive performance environment.

• The outbreak lasted from approximately July to September 1518
• Estimates of participants range from 50 to 400 at the peak — sources vary
• Deaths were reported, attributed to exhaustion, stroke, and heart failure
• The epidemic was confined primarily to Strasbourg, though similar episodes occurred elsewhere
• The council reversed course weeks later, banning music and removing dancers to a shrine

Earlier Episodes: The 1518 Event Was Not Unique

The 1518 episode was the largest and best-documented, but it was not without precedent. Medieval Europe experienced multiple episodes of what chroniclers called "dancing mania" or "choreomania."

The geographic clustering in the Rhine valley and the temporal clustering in periods of severe famine and social stress has been noted by historians.

Theories: What Actually Happened?

No consensus exists among historians and medical researchers. Several hypotheses have been proposed and debated.

Mass Psychogenic Illness (Mass Hysteria)

The most widely accepted modern explanation is mass psychogenic illness (MPI) — a condition in which psychological and social stress produces genuine physical symptoms across a group of people. Historian John Waller, author of the 2008 book A Time to Dance, A Time to Die, argues that Strasbourg in 1518 was experiencing extreme hardship: a plague epidemic in prior years, crop failures, famine, and the anxious climate of the Reformation. The population was in acute psychological distress, and St. Vitus — the patron saint invoked for dancers and those with nervous complaints — had a strong regional cult following. Waller argues the dancing was a trance-like dissociative response to unbearable stress, spread by social contagion through a population already primed to interpret the symptom as a recognizable supernatural affliction.

Ergot Poisoning

An alternative theory attributes the dancing to ergot, a fungus that grows on rye and other grains and contains compounds related to LSD that can cause convulsions, hallucinations, and involuntary muscle spasms. The condition, known as ergotism or St. Anthony's Fire, was endemic in medieval Europe during wet growing seasons that promoted fungal growth. A famine year with contaminated grain stocks could theoretically have triggered mass ergotism.

The ergotism theory has significant problems. Ergot poisoning typically causes convulsions and spasms rather than coordinated dancing. It also produces vasoconstriction and gangrene in extremities — features absent from the 1518 accounts. Most historians now consider the MPI explanation more consistent with the available evidence.

Resolution and Its Significance

The outbreak ended when the remaining dancers were transported to the shrine of St. Vitus at Saverne, where they prayed, wore red shoes (a cure specified in local tradition), and were subjected to religious rituals. The dancing gradually ceased. The city council's final response — removing dancers from the public space, eliminating musical accompaniment, and channeling the episode into a religious rather than civic framework — likely disrupted the social reinforcement mechanism sustaining the behavior.

• The religious interpretation removed dancers from the performative public context that had amplified the contagion
• Modern case studies of MPI outbreaks in schools and workplaces show similar resolution patterns when the affected group is dispersed and the episode "named" as psychological
• The 1518 episode has been analyzed in academic literature on mass psychogenic illness as recently as the 2010s

The Dancing Plague of 1518 remains an extraordinary example of how extreme social stress, shared belief systems, and institutional responses can combine to produce collective behavior that defies easy classification as either purely physical or purely psychological.