The dancing plague (or dance epidemic) of 1518 was a case of dancing mania that occurred in Strasbourg, Alsace, (now modern day France) in the Holy Roman Empire in July 1518. Around 400 people took to dancing for days without rest and, over the period of about one month, some of those affected collapsed or even died of heart attack, stroke, or exhaustion.
The outbreak began in July 1518 when a woman, Mrs. Troffea, began to dance fervently in a street in Strasbourg.[1] This lasted somewhere between four and six days. Within a week, 34 others had joined, and within a month, there were around 400 dancers, predominantly female. Some of these people would die from heart attacks, strokes, or exhaustion.[1] One report indicates that for a period, the plague killed around fifteen people per day.
Waller speculates that the dancing was "stress-induced psychosis" on a mass level, since the region where the people danced was riddled with starvation and disease, and the inhabitants tended to be superstitious. Seven other cases of dancing plague were reported in the same region during the medieval era.[7]
This could have been a florid example of psychogenic movement disorder happening in mass hysteria or mass psychogenic illness, which involves many individuals – small groups to almost 1000 people – suddenly exhibiting the same bizarre behavior.