On Christmas Eve in 1021, 18 people gathered outside a church in the German town of Kölbigk and danced with wild abandon. The priest, unable to perform Mass because of the irreverent din from outside, ordered them to stop. Ignoring him, they held hands and danced a “ring dance of sin”, clapping, leaping, and chanting in unison. The enraged priest, recorded a local chronicler, cursed them to dance for an entire year as a punishment for their outrageous levity. It worked. Not until the following Christmas did the dancers regain control of their limbs. Exhausted and repentant, they fell into a deep sleep. Some of them never awoke.

It might seem improbable to us, but there was nothing in this story that mediaeval people found hard to believe. Compulsive dancing joined that litany of natural and human disasters to be explained in terms of celestial or supernatural forces. But even if much of the chronicler's account is clearly the stuff of legend, we should not dismiss it as purely invention. Plenty of sources indicate that this obscure chronicler may have embellished a real event. The Kölbigk incident is a contender for the first of the dancing plagues.

Later chronicles speak of a bout of unstoppable, and sometimes fatal, dancing in the German town of Erfurt in 1247. Shortly after, 200 people are said to have danced impiously on a bridge over the Moselle River in Maastricht until it collapsed, drowning them all. Likewise, dozens of mediaeval authors recount the terrible compulsion to dance that, in 1374, swept across western Germany, the Low Countries, and northeastern France. Chronicles agree that thousands of people danced in agony for days or weeks, screaming of terrible visions and imploring priests and monks to save their souls. A few decades later, the abbot of a monastery near the city of Trier recalled “an amazing epidemic” in which a collection of hallucinating dancers hopped and leapt for as long as 6 months, some of them dying after breaking “ribs or loins”. On a far larger scale was the outbreak that struck the city of Strasbourg in 1518, consuming as many as 400 people. One chronicle states that it claimed, for a brief period at least, about 15 lives a day as men, women, and children danced in the punishing summer heat. There were also several isolated cases during the 1500s and 1600s, from Switzerland and the Holy Roman Empire, of the mania gripping an individual or entire family.

The Dancing Mania by Hendrick Hondius (1642) after Pieter Brueghel Copyright © 2009 Wellcome Library

The dancing plagues are little remembered today, in part because they seem so unbelievable. But while the incidents at Kölbigk, Erfurt, and Maastricht might be apocryphal, there is no question that the 1374 and 1518 epidemics occurred. Dozens of reliable chronicles from several towns and cities describe the events of 1374. And the course of the 1518 epidemic can be minutely detailed with the help of municipal orders, sermons, and vivid descriptions left behind by the brilliant Renaissance physician, Paracelsus. These outbreaks represent a real and fascinating enigma.

On one thing contemporary and modern writers have agreed: those who danced did so involuntarily. They writhed in pain, screamed for help, and begged for mercy. So what could have impelled them to dance against their will? One theory is that they had ingested ergot, a mould that grew on stalks of ripening rye and can cause hallucinations, spasms, and tremors. Epidemics of ergotism certainly occurred in mediaeval Europe when people ate contaminated flour. But this theory does not seem tenable, since it is unlikely that those poisoned by ergot could have danced for days at a time. Nor would so many people have reacted to its psychotropic chemicals in the same way. The ergotism theory also fails to explain why virtually every outbreak occurred somewhere along the Rhine and Moselle Rivers, areas linked by water but with quite different climates and crops.

We do know, however, that the victims of dancing epidemics were experiencing altered states of consciousness. This is indicated by their extraordinary levels of endurance. In a trance state, they would have been far less conscious of their physical exhaustion and the pain of sore, swollen, and lacerated feet. Onlookers in 1374 also spoke of the afflicted as wild, frenzied, and seeing visions; the dancers yelled out the names of devils, had strange aversions to pointed shoes and the colour red, and said they were drowning in “a red sea of blood”. There is even a drawing of 1564 by Pieter Bruegel the Elder showing a group of women dancing uncontrollably, all of them wearing the distant, distracted, and divorced-from-reality expressions of the deeply entranced.

High levels of psychological distress significantly increase the likelihood of an individual succumbing to an involuntary trance state. It is unlikely to be a coincidence, therefore, that the 1374 dancing plague spread in the areas most savagely hit earlier in the year by the most devastating deluge of the 14th century. The people of Strasbourg and its environs were similarly experiencing acute distress in 1518, after a succession of appalling harvests, the highest grain prices for over a generation, the advent of syphilis, and the recurrence of such old killers as leprosy and the plague. Even by the gruelling standards of the Middle Ages, these were bitterly harsh years for the people of Alsace.

But if despair created the right conditions for an extreme psychological reaction, this does not explain why so many danced in their misery. Why did they not sob, scream, riot, fight, or fall into a sullen silence? This is where anthropological field studies prove to be invaluable. Accounts of “possession rituals” from the Arctic and Andes to the Kalahari and Caribbean show that people are more likely to enter the trance state if they expect it to happen and that entranced participants behave in a ritualistic manner, their thoughts and motions shaped by the spiritual beliefs of their cultures. Female mediums in Madagascar, for instance, take on the distinct personas of the spirits believed to inhabit them. Similarly, the participants in Vodou rituals adopt the roles of specific deities drawn from a pantheon of gods with varying personalities. Were there, then, belief systems in the regions affected by the dancing plague that could have channelled widespread despair into an irresistible urge to dance?

A variety of sources, from altar paintings to chronicles and law books, show that a dread of this punitive affliction formed part of the collective consciousness of the people of the Rhine and Moselle valleys. Those living near these mighty commercial waterways shared a profound fear of wrathful spirits able to inflict a dancing curse. And it is in this region alone, close to the western fringe of the Holy Roman Empire, that confirmed epidemics of dancing occurred. Moreover, these outbreaks nearly always struck in or close to cities affected by earlier dancing epidemics. In short, the epidemiological picture is strikingly consistent with a form of cultural contagion. Only where there was a pre-existing belief in a dancing curse could psychological distress be converted into the form of a frantic dance. Every so often, when physical and mental distress rendered people more than usually suggestible, the spectre of the dancing plague could quickly return. All it then took was for one or a few poor souls, believing themselves to have been subject to the curse, to slip into a spontaneous trance. Then they would unconsciously act out the part of the accursed: dancing, leaping, and hopping for days on end.

The course of the epidemics also suggests that they were driven by pious fear. From the outbreaks of 1374, 1463, and 1518 we know that dancing was thought to be both the affliction and its cure. There are accounts of people who had temporarily recovered their wits, deliberately dancing themselves back into oblivion in the expectation that only in this way would the curse be lifted. For the same reason, in Strasbourg in 1518 the authorities mandated that the dancers go on dancing day and night, to which end they constructed a special stage in the heart of the city where they could move freely. They even hired professional dancers and musicians to keep them in constant motion. The policy was a disaster. From the dramatic escalation in the epidemic it seems that the strategy helped spread a psychic contagion. In fact, nothing could have been better calculated to turn the dance into a full-scale epidemic than making its victims perform their dances in the most public of spaces. The authorities turned a crisis into a nightmare scenario worthy of a canvas by Hieronymus Bosch.

The central role of belief is also apparent in the speed with which epidemics abated once victims had prayed at appropriate shrines or undergone elaborate exorcism rituals. Perhaps more significantly, we have several accounts from the mid to late 1500s of cults of entranced dancing in towns close to the Black Forest and where the Rhine enters the North Sea. Groups of distressed men and women deliberately entered a trance and then danced, accompanied by musicians, towards shrines dedicated to the saints most widely associated with the dancing curse: St Vitus and St John. It seems that a dread of the dancing curse had been harnessed and controlled. A psychic epidemic had been turned into an ecstatic religious ritual.

By the mid-1600s, if not before, outbreaks of compulsive dancing had ceased to torment the people of Europe. Their disappearance coincided with the demise of the fervent supernaturalism that had sustained them; in the late 17th century the term “St Vitus' Dance” was appropriated to describe a quite different medical condition. But these bizarre events are well worth remembering. For they provide an object lesson in the power of our beliefs and expectations to shape the expression of psychological distress. In an age dominated by genetic explanations, the dancing plagues remind us that the symptoms of mental illnesses are not fixed and unchanging, but can be modified by changing cultural milieus. At the same time, the phenomenon of the dancing mania, in all its rich perversity, reveals the extremes to which fear and supernaturalism can lead us.

Further reading Backman, 1952. Backman LE Classen E Religious Dances in the Christian Church and in Popular Medicine. George Allen & Unwin , London Google Scholar Bourguignon, 1991. Bourguignon E Possession. Waveland Press , Prospect Heights, IL Google Scholar Midelfort, 1999. Midelfort EHC A History of Madness in Sixteenth-Century Germany. Stanford University Press , Stanford Google Scholar Waller, 2008. Waller J A Time to Dance. A Time to Die: The Extraordinary Story of the Dancing Plague of 1518. Icon Books , Cambridge Google Scholar