thumb|250px|Dancing mania on a pilgrimage to the church at [[Sint-Jans-Molenbeek, a 1642 engraving by Hendrick Hondius after a 1564 drawing by Pieter Brueghel the Elder]]
Dancing mania (also known as dancing plague, choreomania, St. John's Dance, tarantism and St. Vitus' Dance) was a phenomenon which 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 adults and children who danced until, allegedly, they collapsed from exhaustion and injuries, and sometimes died. One of the first major outbreaks was in Aachen, in the Holy Roman Empire (within modern-day Germany), in 1374, and it quickly spread throughout Europe; one particularly notable outbreak occurred in Strasbourg in 1518 in Alsace, also in the Holy Roman Empire (within modern-day France).
Affecting thousands of people across several centuries, dancing mania was not an isolated event, and was well documented in contemporary reports. It was nevertheless poorly understood, and remedies were based on guesswork. Often musicians accompanied dancers, due to a belief that music would treat the mania, but this tactic sometimes backfired by encouraging more to join in. 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 speculated to have been a mass psychogenic illness, in which physical symptoms with no known physical cause are observed to affect a group of people, as a form of social influence. and is also known as "dancing plague". The term was coined by Paracelsus, or St. Vitus, and was therefore known as "St. Vitus' Dance" or "St. John's Dance". Victims of dancing mania often ended their processions at places dedicated to that saint,
St. Vitus' Dance was diagnosed, in the 17th century, as Sydenham's chorea. Dancing mania has also been known as epidemic chorea One of the earliest-known incidents occurred sometime in the 1020s in Bernburg, where 18 peasants began singing and dancing around a church, disturbing a Christmas Eve service.
Characteristics
The outbreaks of dancing mania varied, and several characteristics of it have been recorded. Generally occurring in times of hardship, days, weeks, and even months. Bartholomew also notes that observers of dancing mania were sometimes treated violently if they refused to join in. In the end, most simply dropped down, overwhelmed with exhaustion. Ergotism can cause hallucinations and convulsions, but cannot account for the other strange behaviour most commonly identified with dancing mania.
Hetherington and Munro describe dancing mania as a result of "shared stress";
According to Deborah Hyde, the spontaneous spread of this phenomenon through social networks played a significant role:
: "It’s hard to deny that the dancing mania was marked by social contagion exacerbated by stress. Outbreaks occurred along trade routes or reoccurred in the same areas – where people had knowledge of the format, in other words. Beliefs and behaviour can travel just like pathogens."