The “Dancing Plague” sounds like a term that the newer generations would use to describe a joyful activity. But, the term had a much more sinister meaning in the 16th century.
In 1518, a woman named Frau Troffe started dancing on the streets of Strasbourg, a city that is now part of modern France. She went to dance constantly for one week, after which several more people joined in. According to accounts, the number of dancers just kept in the following weeks and reached 400 at one point.
The dancers were so focused on their activity that they danced until falling from exhaustion, wearing out the skin of their feet, or even dying. The number of fatalities from the “dancing plague of 1518” varies depending on the sources.
Eventually, the “dancing plague” calmed down after two months following an intervention of the city’s authorities, who sent the dancers to a mountain shrine to pray.
The true cause of the “dancing plague” remains unknown to date. One explanation is that the dancers got food poisoning after consuming ergot fungi, which contain the psychoactive chemical ergotamine. Another explanation is that the event is an example of stress-induced mass hysteria, which could have been triggered by the stress due to unforgiving living conditions in Strasbourg at the time.