The dancing plague of Strasbourg, 1518

It all began with a few folks dancing outside in the scorching heat of June. They danced through the night and into the next day, arms swinging, bodies swaying, and outfits wet in sweating. They were still going days later, barely stopping to eat or drink and seemingly indifferent to rising exhaustion and the pain of damaged feet. Hundreds more were dancing in a frantic manner by the time the officials arrived.

This was not, however, one of those 1980s gatherings that commenced in a rural lay-by and concluded in a muddy field. Actually, it's one of the weirdest outbreaks ever documented. During summer, in the French city of Strasbourg, it transpired 500 years ago. Hundreds of people acquired an urge to dance there over the course of three blistering summer months in the year 1518. The dancing continued until, much to the delight of the onlookers, several of the participants fell and died on the spot. What was going on exactly?

The "dancing plague of Strasbourg" began in mid-July 1518, according to an account published in the 1530s by the irascible but brilliant physician Paracelsus, when an alone woman stepped outside her residence and grooved for a few days on end. Within a week, hundreds more were overcome by the same overwhelming desire.

The city's wealthiest burghers were not pleased. One of them, writer Sebastian Brant, had dedicated a chapter to the stupidity of ballet in his moralizing book Ship of Fools. He and his colleagues' city councilors were confused by the mayhem in the streets and sought advice from local physicians, who judged the dancing to be the consequence of "overheated blood" on the brain, in accordance with conventional medical understanding.

The councilors agreed on what they considered was the right course of action — more dancing! They seized guild rooms, ordered the dismantling of an open-air grain market, and set a stage near to the horse fair. They took the frenzied dancers to these locations in the hopes of throwing off the disease by sustaining frenetic motion. The burghers even hired pipers and drummers, as well as "strong men" who would hold the afflicted's bodies as they spun and swung. In a sight as demonically absurd as anything envisioned by Hieronymus Bosch, those at the food retail sector and horse fair kept dancing beneath the full light of the August sun.

What occurred next is described in a poem in the municipal archives: "In their lunacy, people continued on dancing until they fell asleep and many perished." The council was aware that it had committed a blunder. They chose a period of forced penance and forbade music and dancing in public, believing the dancers were suffering from heavenly anger rather than burning brains. Finally, the dancers were escorted to a shrine devoted to St Vitus, which was hidden in a musty grotto in the hills above Saverne, where their wounded feet were fitted in red shoes and they were walked around a wooden figurine of the saint. According to the chronicles, most of the people stopped their wild excursions in the following weeks. The outbreak had come to a close.

Why did the burghers recommend greater dancing as a cure for a fried brain? Why was it necessary for the dancers to wear red shoes? And how many people perished as a result?

Several additional outbreaks of dance had occurred in previous ages, involving hundreds or just a few people, almost all in towns and cities bordering the Rhine. News and beliefs traveled with the merchants, pilgrims, and warriors that sailed these rivers. St Vitus' ability to punish sinners by having them dance appears to have become ingrained in the region's cultural psyche. A picture at Cologne Cathedral, more than 200 miles downstream from Strasbourg, dramatizes the curse: three men joyfully dance beneath an icon of St Vitus, their faces bearing the crazed looks.

Beliefs in the supernatural agency can have a significant impact on human actions. "Spirit possession," in which individuals act as if their souls have been taken over by a spirit or divinity, is a famous example. Erika Bourguignon, an anthropologist from the United States, has written on how growing up in a "belief environment," where spirit possession is regarded seriously, prepares people to enter a dissociative mental state, in which regular awareness is incapacitated. People then react in accordance with culturally established ideals of how possessed people should act. Nuns used to writhe, spasm, foam at the mouth, make obscene gestures and proposals, climb trees, and miaow like cats at European convents before the early 1700s. The nuns lived in societies that pushed them to worry about sin and were immersed in mystical supernaturalism, which explains their unusual behavior. Those who believed demons had infiltrated their souls were prone to dissociative experiences in which they acted exactly what theologians and exorcists started the diabolically possessed do. The possessed state expanded to witnesses who had the same religious concerns in such circumstances.

These findings might very well relate to the events of 1518 in Strasbourg. The curse of St Vitus is the type of supernaturalist belief that can induce dissociation experiences in the suggestible. Most people assumed the disease was caused by an infuriated St Vitus, according to the chronicles. So all it took for a handful of the devoted and emotionally vulnerable to believe St Vitus was after they were for them to get into a trance state and feel compelled to dance for days. If the dancing craze was a case of mass psychogenic disease, we can see why so many people were affected: few acts could have been more favorable to initiating an all-out mental pandemic than the councilor's decision to herd the dancers into the city's most public areas. Other city dwellers were made vulnerable by their presence, as their minds were drawn to their own faults and the chance that they might be next.

Another key requirement for the onset of psychogenic sickness in Strasbourg in the early 1500s was that the chronicles record a lot of the suffering that causes a high level of suggestibility. Widespread hardship was caused by social and religious tensions, terrible new illnesses, harvest failures, and skyrocketing wheat prices. With devastating brevity, a historian described 1517 as a "poor year." Orphanages, hospitals, and shelters were bursting at the seams the next summer. These were excellent circumstances for some of the city's poor to believe that God was furious with them and that St Vitus was stalking the streets.

Fortunately, the dancing pandemic of 1518 was Europe's last of its sort. The risk of future breakouts likely decreased along with the belief systems that had maintained them. The dance craze emphasizes the importance of the cultural environment in shaping how psychological anguish is conveyed.