In 1518 a Strasbourg Woman Danced for Days. Then Hundreds Joined Her.

On a summer day in 1518, a woman the chronicles call Frau Troffea stepped into a narrow street in Strasbourg and began dancing. She did not stop. Within a week, thirty-four neighbours had joined her. By the end of the month, contemporary records put the number between fifty and four hundred, and several were dead — from heart failure, stroke, or sheer exhaustion.

The sources are unusually good for an episode that sounds folkloric. Strasbourg was a literate, well-administered Free Imperial City; physicians' notes, council minutes, and printed broadsides survive. The historian John Waller, in A Time to Dance, A Time to Die (2008), reconstructed the event in detail.

The city's response is the strangest part. Strasbourg's physicians ruled out demonic possession and diagnosed "hot blood," recommending that the dancers dance the affliction out of their bodies. The council hired musicians, cleared a stage near the horse market, and watched. The intervention seems to have made things worse. Only when authorities finally banned music and shipped the most affected dancers to a mountain shrine did the outbreak subside.

No single cause has been proved. Ergot poisoning — fungal contamination of rye — was once popular but is shaky: ergotism normally produces convulsions and gangrene, not stamina. Waller argues for mass psychogenic illness, the kind documented many times since: a population under acute distress, a culturally available script (the legend of St. Vitus, who could curse people with uncontrollable dancing), and a trigger.

1518 had the script and the stress. Famine and disease had been hammering the upper Rhine for two years. One woman started, the city watched, and the trance spread through the audience.