Choreomania aka dancing plague: was a social phenomenon that occurred primarily in mainland Europe between the 14th and 17th centuries. It involved groups of people dancing erratically, sometimes thousands at a time. The mania affected men, women, and children, who danced until they collapsed from exhaustion.
There is no consensus among modern-day scholars as to the cause of dancing mania.The several theories proposed range from religious cults being behind the processions to people dancing to relieve themselves of stress and put the poverty of the period out of their minds. It is, however, thought to be as a mass psychogenic illness in which the occurrence of similar physical symptoms, with no known physical cause, affect a large group of people as a form of social influence.