In 1518, one woman started dancing in the street and couldn't stop — and within weeks, 400 people had joined in a terrifying, possibly fatal frenzy no one could explain.
In July 1518, a woman named Frau Troffea stepped into a street in Strasbourg and began dancing uncontrollably. She danced for a full week without stopping. Within days, dozens of others had joined her — and by August, the 'dancing plague' had claimed up to 400 victims across the city.
The victims showed no signs of joy. Their bodies convulsed, their arms thrashed, and their eyes were described as vacant and expressionless. Blood pooled into their swollen feet until they bled into their shoes. At the height of the outbreak, it was claimed that up to 15 people per day were dying from heart attacks, strokes, or sheer exhaustion.
No one knew what was causing it, so the city authorities tried a bizarre remedy: they prescribed the afflicted to 'dance themselves free of it.' Guild halls were refurbished into makeshift dance floors, musicians were hired, and strong men were employed to keep the dancers upright. This only made things worse, drawing more people in.
The city council eventually reversed course entirely — banning all public music and dancing, and ordering the afflicted to make a pilgrimage to a mountain shrine of Saint Vitus, the patron saint believed to be punishing them. Wearing red shoes sprinkled with holy water and painted with crosses, the dancers were led up the mountain to pray for forgiveness. The plague subsided in September 1518.
The most widely accepted modern explanation is stress-induced mass psychogenic illness. The region of Alsace was suffering famine, disease, and extreme poverty at the time. Historian John Waller argues the dancing was a collective psychosis — a dissociative response to unbearable social pressure in a population already steeped in superstition about Saint Vitus's curse.
The ergot-poisoning theory — that contaminated bread caused hallucinations similar to LSD — has been largely dismissed. Ergot poisoning would not allow sustained dancing for days, and would not affect hundreds of people in the same choreographic way. The Dancing Plague remains one of history's most bewildering and unsettling mass events.