In the annals of history, few phenomena are as bizarre and unsettling as the Dancing Plagues that swept through medieval Europe. Imagine the scene: it’s 1374, and in towns along the Rhine River valley, hundreds are inexplicably seized by an overwhelming urge to dance. They move relentlessly, barely pausing for food or rest, for hours, sometimes days on end. These were the afflicted of a baffling epidemic, one of the most peculiar afflictions ever recorded in Western history. Within weeks, this mania had spread across northeastern France and the Netherlands, only receding after months of relentless dancing. While sporadic outbreaks occurred in the subsequent century, the phenomenon returned with terrifying intensity in Strasbourg in 1518. Chronicles of the time recount that approximately 400 individuals, men, women, and children, were consumed by this dancing frenzy, leading to numerous deaths (Waller, 2008).
The Strasbourg dancing epidemic wasn’t an isolated incident of inexplicable compulsion during this era. Not long before, in 1491, a Spanish Netherlands nunnery witnessed an equally strange outbreak. Nuns were reported to be ‘possessed,’ driven by unseen forces to behave like animals – racing like dogs, mimicking birds by jumping from trees, or meowing and clawing at tree trunks like cats. These possession epidemics, while not exclusive to nunneries, disproportionately affected religious women (Newman, 1998). Over the following two centuries, from Rome to Paris, countless nuns descended into states of frenzied delirium. They foamed at the mouth, screamed, convulsed, made sexual advances towards exorcists and priests, and confessed to intimate encounters with devils or even Christ.
While these events might seem like fantastical tales, they are substantiated by compelling historical evidence. The dancing plagues are documented in detail by numerous physicians, chroniclers, monks, and priests. For the 1518 Strasbourg outbreak, we even have access to the frantic municipal orders issued by city authorities during the epidemic (Midelfort, 1999; Waller, 2008). Similarly, trial records and Inquisition archives offer extensive and vivid accounts of nuns engaging in the most peculiar behaviors and uttering the strangest pronouncements (Sluhovsky, 2002).
Throughout history, writers and scholars have attempted to interpret these strange and often deadly crises. One theory suggested that the dancing maniacs of 1374 and 1518 were part of a heretical dancing cult. However, contemporary observers clearly described the dancing as a sickness. Even the Church, known for its swift suppression of heresies, viewed the dancers as victims of a terrible affliction, whether natural or divine. In more recent times, biological explanations have gained traction, proposing that these epidemic manias were caused by ergot ingestion, a mold containing psychotropic chemicals (Backman, 1952; Matossian, 1989).
Nevertheless, extensive research in psychology, history, and anthropology points towards a different, more compelling explanation: the dancing plagues and possession epidemics in European nunneries were classic examples of mass psychogenic illness.
Unpacking Altered States of Consciousness
A crucial insight into the origins of these bizarre outbreaks lies in their apparent connection to dissociative trance, a state characterized by a significant loss of self-control. It’s difficult to fathom individuals dancing for days, enduring bruised and bloodied feet, without entering an altered state of consciousness. Eyewitness accounts corroborate this notion of altered awareness. Observers described the dancing maniacs of 1374 as wild, frenzied, and experiencing visions. One account noted that while dancing, “their minds were no longer clear,” while another described them “raging like beasts over the land” after exhausting themselves through dancing and jumping (Backman, 1952). Similarly, the possessed nuns, documented in chronicles, legal records, theological texts, and Inquisition archives, were also subject to dissociative trance (Newman, 1998; Rosen, 1968). While some nuns might have feigned demonic behavior to gain attention (Walker, 1981), the detailed observations of meticulous inquisitors leave little doubt that genuine trance states were involved in most cases.
How can we explain these epidemics of dissociation? Ergot poisoning could potentially induce hallucinations and convulsions in nuns who consumed contaminated bread, but it’s highly improbable that ergotism would cause the relentless dancing associated with dancing plagues (Berger, 1931). Furthermore, there’s no evidence to suggest that the diet of mass possession victims played a role. Instead, compelling evidence suggests that communities experiencing profound fear and depression were unusually susceptible to epidemic possession. Given the well-established link between psychological stress and dissociation, this correlation strongly indicates mass psychogenic illness as the underlying cause.
The Role of Fear and Despair
The periods preceding the dancing epidemics were marked by exceptional hardship. The 1374 outbreak coincided with areas devastated by one of the worst floods of the century earlier that year. Historical accounts describe Rhine floodwaters rising 34 feet, inundating town walls, submerging homes and marketplaces, and carrying decomposing animal carcasses through the streets (Backman, 1952). In the decade leading up to the 1518 dancing plague in Strasbourg, famine, disease, and extreme cold caused widespread despair in the city and its surroundings (Rapp, 1974). Bread prices soared to generational highs, throngs of starving farmers and vine growers sought refuge at the city gates, and old scourges like leprosy and plague were compounded by the terrifying emergence of syphilis.
These were times of intense trauma and societal strain. While nuns were shielded from some of the daily hardships of the outside world, nunneries themselves could become breeding grounds for psychological distress. Even in well-managed communities, unhappiness was inevitable. Women were often placed in convents based on their parents’ wishes, rather than personal piety. Once within the cloistered walls, escape was exceedingly difficult. Paradoxically, those most devoted to spiritual life could also be the most vulnerable. Haunted by feelings of inadequacy in meeting the rigorous standards of holiness demanded by their orders, many nuns grappled with intense fear of eternal damnation for impure thoughts or deeds.
A striking example is Jeanne des Anges, Mother Superior of the Loudun nunnery in southern France. In 1627, she became infatuated with a local priest, Father Grandier. “When I did not see him,” she later confessed, “I burned with desire for him.” This forbidden desire led to overwhelming feelings of guilt and worthlessness. After weeks of intense penance and self-examination, Jeanne entered a dissociative state, repeatedly accusing Grandier of conspiring with Satan to incite her lust. Within days, several other nuns followed suit, all hysterically pointing fingers at the unfortunate priest. Following an Inquisition investigation, Father Grandier was burned at the stake (de Certeau, 2000). As illustrated by the Loudun case, repressed desires and guilt could trigger collective psychological breakdowns. This partly explains the alarming lewdness exhibited by dissociating nuns during their possession attacks: lifting their habits, simulating sexual acts, and giving their demons names like “Dog’s Dick,” “Fornication,” and even “Ash-Coloured Pussy.” Guilt and desire could indeed drive a nun to distraction (Sluhovsky, 2002).
The resilience of many nuns was further tested by the evangelical reform movement that swept through their communities from the early 1400s. Reformers, aiming to reinstate the stringent spiritual codes of earlier centuries, mandated bland diets, rejection of vanity, rigorous abstinence and self-abasement, and constant meditation on Satan and hellfire. Many nuns, often from noble or wealthy families, struggled to adapt to tasteless meals, hard beds, and evenings devoid of music and conversation. Consequently, the arrival of reformist Mother Superiors often precipitated mass possession outbreaks. The Ursuline nuns of Auxonne in eastern France, for instance, experienced a possession crisis in 1658 after Barbe Buvée, an evangelical reformer, was appointed as their Mother Superior. For years, distressed and dissociating nuns accused her of witchcraft, infanticide, and lesbianism. While Barbe Buvée was eventually exonerated, she was discreetly reassigned to another nunnery, and the possession crisis subsided (Sluhovsky, 2002).
Mass possession also affected secular communities, and stress played a clear role there as well. The girls whose “grievous fits” and “hideous clamors and screeching” ignited the Salem witch trials in New England in 1692 belonged to a community fractured by internal conflicts (Demos, 1983). They also lived in constant fear of attacks from Native American tribes, who had already killed parents and relatives of some of the accusers at the heart of the witchcraft accusations (Norton, 2003).
Fear and anguish emerge as common threads linking dancing plagues and possession crises. However, this is only part of the explanation.
Cultural Beliefs: Rude Devils and Cursing Saints
Studies of possession cults in numerous modern cultures, from Haiti to the Arctic, reveal that the likelihood of experiencing dissociative trance is heightened when individuals already believe in the possibility of spirit possession (Rouget, 1985). Minds can be conditioned, through learning or implicit exposure, to enter altered states. Anthropologist Erika Bourguignon (1991) coined the term “environment of belief” to describe the shared set of ideas about the spirit world that community members absorb, thus preparing them for possession states. Formal training isn’t necessary; the populations of 1374 and 1518 existed within an environment of belief that acknowledged the threat of divine curses, possession, or bewitchment. They didn’t intentionally seek trance states, but their metaphysical beliefs made such states possible.
Similarly, understanding the cultural context is crucial to explain why possession crises were so prevalent in religious houses and why women were disproportionately affected by diabolical possession. Nuns’ daily lives were steeped in mystical supernaturalism, their imaginations filled with devils, demons, Satanic familiars, and vengeful saints. Their implicit belief in possession made them more susceptible. Evangelical Mother Superiors often inadvertently increased this vulnerability by encouraging trance and ecstatic worship, which could predispose nuns to involuntary possession states. Furthermore, early modern women were taught that, as inheritors of Eve’s sin, they were more prone to succumbing to Satan – a misogynistic idea that amplified their suggestibility.
Therefore, when a particularly distressed nun began to faint, foam at the mouth, convulse, and speak in strange tongues, there was always a risk that her more suggestible sisters would start exhibiting similar dissociative symptoms, convinced that Satan was lurking within their cloister, seeking impure souls.
Modern anthropology and psychology also demonstrate how beliefs and expectations shape the individual experience of dissociation. In societies where trance states are encouraged for spirit communication, individuals typically behave in ways culturally prescribed (Katz, 1982; Sharp, 1993). We have every reason to believe that the victims of dancing plagues and possession epidemics were also acting within the framework of their world’s rich theology.
The cultural underpinnings of dancing plagues are evident in their concentration in communities where pre-existing beliefs in dancing curses from Heaven or Hell were present. In 1374, dancers believed Satan had unleashed an irresistible dance, leading them to dance incessantly, plead for divine intervention, flock to holy sites, and willingly undergo exorcism (Backman, 1952). In 1518 Strasbourg, the population believed Saint Vitus had sent a dancing curse (Martin, 1914; Waller, 2008). Consequently, upon entering a dissociative state, they acted according to the St. Vitus myth, dancing for days. The epidemic spread, as in 1374, because each new victim reinforced the belief in supernatural forces. Ironically, Strasbourg authorities exacerbated the outbreak by gathering dancers in public spaces and allowing them to continue dancing (Waller, 2008), amplifying the power of suggestion.
Theological conventions also shaped the behavior of demonically possessed nuns. Notably, possession epidemics primarily occurred within a 300-year period, from around 1400 to the early 1700s. This timeframe coincides with religious writers emphasizing the possibility of such events (Newman 1998). Theologians, inquisitors, and exorcists established the “rules” of demonic possession, which dissociating nuns then unconsciously adopted: writhing, foaming, convulsing, dancing, laughing, speaking in tongues, and making obscene gestures and propositions. These shocking displays were stereotypical performances based on deeply ingrained beliefs about Satan’s depravity, drawn from religious texts and accounts of prior possessions. For centuries, then, distress and religious fear combined to produce epidemics of dancing and possession.
The Interplay of Body and Mind
In 1749, a German nunnery in Würzburg experienced an epidemic of screaming, writhing, and trance, culminating in the execution of a woman accused of witchcraft. However, by this time, dancing plagues had vanished, and possession crises were becoming rare. The incidence of possession declined with the rise of modern rationalism (Bartholomew, 2001). Subsequently, mass outbreaks of dissociation tended to be confined to highly controlled environments like factories and schools, often triggered by unfounded fears of poisoning or toxic exposure (see box below). Even these outbreaks are now less common in the Western world. Yet, dancing plagues and the experiences of demonically possessed nuns still offer valuable insights into human responses to stress. These events vividly illustrate the profound influence of context in shaping the expression of anguish and fear. Historian Edward Shorter argues that the “symptom pool” for psychosomatic illness has varied significantly across time and cultures (Shorter, 1992). The fluctuating prevalence of conversion disorder, somatoform disorder, and dissociative trance is at least partially attributable to evolving social norms and expectations (Nandi et al., 1992). The madnesses of the past reveal much about the societies that fostered them. But wild epidemics of dancing and possession also serve as potent reminders of the inherent instability of many psychiatric conditions.
- John Waller is in the Department of History at Michigan State University, and is the author of A Time to Dance, a Time to Die [email protected]
BOX: Modern Hysterias
While dancing plagues may be relics of the past, mass psychogenic illness (MPI) remains a relevant aspect of the human experience. MPI is defined as the “collective occurrence of physical symptoms and related beliefs among two or more persons in the absence of an identifiable pathogen” (Colligan & Murphy, 1982). Simon Wessely (1987) distinguishes between two types of MPI outbreaks: “mass anxiety hysteria” and “mass motor hysteria.”
Mass anxiety hysteria typically involves the sudden onset of intense anxiety in response to a perceived, but false, threat. In Western settings, unfounded fears of poisoning or toxic chemical exposure have triggered classic stress responses such as fainting, nausea, weakness, and hyperventilation. For example, in a Blackburn school in 1965, 141 students experienced psychogenic dizziness, nausea, spasms, and shortness of breath after several girls fainted publicly (Bartholomew & Wessely, 2002). Unless amplified by media or official validation, mass anxiety hysteria outbreaks usually subside within a few days.
In contrast, mass motor hysteria often requires a prolonged period of psychological tension buildup, which then manifests as dissociative states, conversion symptoms, and other psychomotor abnormalities. These outbreaks can persist for weeks or months. They are often shaped by supernatural beliefs akin to those that fueled dancing mania and nunnery possession crises in Europe. In modern Malaysia and Singapore, for instance, factory workers, often from rural communities with strong beliefs in the spirit world, may struggle to adapt to factory regimentation. Some enter dissociative states, behaving in ways consistent with their culture’s understanding of spirit possession. MPI can emerge when coworkers share similar beliefs and experience significant psychological strain. These outbreaks are often resolved through religious rituals, sometimes involving animal sacrifice (Phoon, 1982). Mass motor hysteria frequently occurs in schools, both in Western and non-Western contexts. In 1962, at a mission school near Lake Tanganyika, several girls developed uncontrollable laughing and crying, which spread to surrounding communities (Rankin & Philip, 1963). Similar laughing epidemics have been documented in Zambia and Uganda. Central African schools are particularly susceptible to mass motor hysteria outbreaks. In late 2008, at a Tanzanian school, girls facing exam pressure responded by dissociating: some fainted, others sobbed, yelled, or ran around the school grounds.
Conversion symptoms can also dominate MPI outbreaks. In 2006, approximately 600 students at a strict all-girls school in Mexico City developed paralysis and nausea lasting for days or weeks. Similar MPI cases have been reported in European and North American schools. In a North Carolina school in 2002, a dozen students experienced seizures or paroxysmal episodes over four months (Roach and Langley, 2004). In many such cases, victims undergo extensive medical evaluations before a lack of organic cause leads to a diagnosis of MPI.
“Mass hysteria” is also used to describe situations where groups act on beliefs that gain undue prominence during times of social and economic instability. For example, parts of Southeast Asia experience periodic epidemics of “Koro,” the fear that one’s genitals are shrinking into the body. “Koro” is fueled by belief in an evil spirit causing genital retraction. Death is believed to follow complete disappearance of the penis, nipples, or vulva into the body, leading men to sometimes impale their penises to prevent retraction (Bartholomew, 2001). A similar phenomenon has been recorded in parts of West Africa, where men claim their penises have been shrunk or stolen by magic. Accused “penis-thieves” are sometimes violently attacked, even lynched; at least 14 were killed in Nigeria in 2001 (Dzokoto & Adams, 2005).
Differentiating mass anxiety hysteria and mass motor hysteria from actual environmental hazard exposures can be challenging. Experts have identified indicators suggesting a psychogenic origin for sudden illness outbreaks in groups. These include the absence of a plausible organic basis, occurrence within a relatively closed group, and pre-existing high stress levels. However, thorough testing for toxic or pathogenic exposures is always crucial. A 1990 case in London, where children at a primary school displayed MPI symptoms (nausea, vomiting, abdominal pain, over-breathing), initially seemed like classic mass hysteria. However, it was later found to be pesticide poisoning from contaminated cucumbers (Bartholomew, 2001).
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