The Dancing Plague of 1518

A strange thing happened in Strasbourg, France, during the summer of 1518. A woman began to dance - uncontrollably, incessantly. Thus began the Dancing Plague of 1518.

She was still dancing several days later. Within a week about 100 people had been consumed by the same irresistible urge to dance. The authorities were convinced that the afflicted would only recover if they danced day and night.

So guildhalls were set aside for them to dance in, musicians were hired to play pipes and drums to keep them moving, and professional dancers were paid to keep them on their feet. Within days those with weak hearts started to die.

By the end of August 1518 about 400 people had experienced the madness. Finally they were loaded aboard wagons and taken to a healing shrine. Not until early September did the epidemic recede.

Theories abound as to the epidemic's source. Some point to ergot, the hallucinogenic fungus common to wheat crops during the Middle Ages, as the culprit. Others, such as historian John Wallis (who notes "that the event took place is undisputed"), suggest mass hysteria - specifically, "'mass psychogenic illness,' a form of mass hysteria usually preceded by intolerable levels of psychological distress, caused the dancing epidemic." Whatever the cause, this well-documented incident remains bizarre. And it wasn't isolated, either: "At least seven other outbreaks of the dancing epidemic occurred in medieval Europe, mostly in the areas surrounding Strasbourg."

You can read more here and here.