The Dancing Plague of 1518

A look at Strasbourg’s mysterious dancing mania, the hardship and fear that fueled it, and what it teaches us about psychology, culture, and collective behavior

This article has been many years in the making. My fascination with the psychology of social contagion began long before I knew anything about the Dancing Plague of 1518. It started with the viral video of the “Dancing Guy” at Sasquatch 2009, where one man on a hillside began moving to music. Within minutes, others joined him, and soon a large crowd was caught up in the moment. It was a vivid example of how quickly behavior can spread.

Years later, I first came across a reference to the Dancing Plague of 1518 in Matt Haig’s book Notes on a Nervous Planet, where he noted that “…over the course of a month, 400 people in Strasbourg danced themselves to the point of collapse, and in some cases death, for no understandable reason. No music was even playing.”

More recently, I was reminded of the Dancing Plague while listening to a podcast devoted to the subject, which reignited my interest in how extraordinary episodes of group behavior can unfold.

The Outbreak Begins

In mid-July 1518, the people of Strasbourg were stunned when a woman named Frau Troffea began dancing in the street without rest or reason. Within days, dozens more joined her. By August, estimates ranged from dozens to several hundred people dancing day and night. Many stopped eating or sleeping. Some reportedly collapsed from exhaustion or stroke, and chroniclers even claimed deaths. Historians still debate the exact numbers, but the ordeal left the city scarred.

A City Under Pressure

The roots of the outbreak were woven through environmental, social, religious, and psychological distress. Several conditions converged.

Famine and malnutrition. Harsh weather and repeated crop failures in prior years led to widespread hunger. In particular, “The Bad Year” of 1516–17 left many people weakened.

Disease and mortality. Syphilis, smallpox, leprosy, and the “English Sweat” (a frightening illness marked by delirium, fever, and often death within hours) had also swept through the region.

Religious upheaval and fear. People’s faith was shaken by corruption among clergy, failing church institutions, and ominous apocalyptic signs. Belief in saints, curses, and divine punishment still carried great weight in popular culture.

Together, these pressures created an atmosphere of strain and vulnerability. In such a context, bizarre behavior, whether one woman’s dancing or a rumor of divine wrath, could resonate powerfully and spread quickly through a community bound by fear and uncertainty.

Early Explanations and Responses

Faced with crowds of people dancing uncontrollably in the streets, Strasbourg’s leaders struggled to make sense of what was happening. Their responses reflected the mix of medical knowledge, cultural beliefs, and religious traditions of the early 16th century.

Medical interpretations. Local physicians, working within the framework of Galenic theory, diagnosed the dancers as suffering from an excess of “hot blood.” In their view, vigorous movement was the best way to expel the heat. On this basis, the city cleared spaces such as guildhalls and markets, even building wooden stages so the dancers could move freely. Musicians and professional dancers were hired to accompany them. Far from containing the crisis, however, these measures appear to have drawn larger crowds and prolonged the spectacle.

Religious interpretations. As medical approaches faltered, the authorities turned to spiritual remedies. The phenomenon was reinterpreted as a curse sent by St. Vitus, a martyr and one of the Fourteen Holy Helpers venerated across medieval Europe. St. Vitus was believed to have the power both to heal epilepsy and to inflict compulsive dancing when angered, which explains why the Strasbourg dancers were thought to be under his wrath. To counter this, civic leaders organized rituals of repentance, restricted public music and dancing, and eventually sent groups of afflicted dancers on pilgrimages to shrines dedicated to St. Vitus. There, ceremonies involving prayer, holy water, and offerings were carried out. Chroniclers reported that these interventions coincided with the eventual decline of the outbreak.

Modern Theories of Causation

While contemporaries in Strasbourg saw the dancing plague as either a medical imbalance or a divine curse, modern historians and psychologists view it through different lenses. Two explanations dominate current scholarship: mass psychogenic illness and ergot poisoning.

Mass Psychogenic Illness (MPI)

The leading theory is that the Strasbourg outbreak was a case of mass psychogenic illness (MPI), sometimes called mass hysteria. This occurs when groups of people develop physical or behavioral symptoms without an identifiable organic cause, often in response to intense psychological stress. This theory gains support when we look at many similar outbreaks recorded throughout history. For example, the Wikipedia “List of Mass Panic Cases” catalogues numerous events where fear, rumor, or social stress led groups to exhibit shared physical or behavioral symptoms without identifiable medical causes.

Other Hypotheses and Their Limits

A second theory sometimes proposed is ergot poisoning. Ergot is a hallucinogenic fungus that grows on damp rye and has been linked to convulsions and delusions. However, this is often viewed as implausible: ergot restricts blood flow to the extremities, making sustained dancing for days virtually impossible. Moreover, the geographic and temporal spread of the outbreak does not fit the pattern of ergotism.

Other biological or infectious explanations have also been suggested, but there is little supporting evidence. Chroniclers did not describe consistent symptoms of disease, nor do their accounts resemble the course of known contagions.

The Psychology of Social Contagion

If mass psychogenic illness provides the medical-psychological framework, social contagion explains how such outbreaks spread. Social contagion refers to the way behaviors, beliefs, and emotions can ripple through groups, not through pathogens, but through observation, imitation, and shared meaning.

Psychology has a long history of studying how people “catch” feelings or actions from those around them. For example, research on emotional contagion shows that individuals unconsciously mimic the expressions and moods of others, leading to synchronized emotional states across groups. In high-stress contexts like Strasbourg in 1518, this mechanism could help explain why witnessing one person dance might make others feel compelled to join.

Modern neuroscience adds another layer. Studies using brain imaging suggest that mirror neurons may play a role in our tendency to unconsciously copy the actions of others, creating a neural basis for imitative behaviors. While mirror neurons alone do not explain something as dramatic as the Strasbourg outbreak, they highlight how deeply social humans are inclined to align with those around them.

Seen this way, the dancing plague was not merely a medieval oddity. It was an extreme example of mechanisms still visible today: stress priming individuals, cultural beliefs shaping expression, and social contagion amplifying the response until hundreds were swept into the same behavioral rhythm.

Final Thoughts

The Dancing Plague of 1518 is more than just a curious story from the past. It offers a striking reminder of how human behavior can be shaped and amplified by culture, belief, and shared emotion. When stress runs high, people can find themselves swept into patterns of action that feel irresistible at the time.

We see echoes of this in everyday life: the contagious pull of a yawn, the surge of emotion in a chanting crowd, or the darker spiral of group violence. Each reminds us that behavior spreads not only through choice but also through powerful social currents.

So what does this mean for us? It is a call to notice how our own environments shape the way we think, feel, and act. And it is an invitation to reflect: if you had been in Strasbourg in 1518, or at Sasquatch in 2009, would you have joined in the dance?

I’d love to hear your thoughts or experiences with moments where group energy carried you along.

Fun Fact

Did you know that the Dancing Plague has inspired modern music? Florence + The Machine released a track called Choreomania on their 2022 album Dance Fever. The song grew out of Florence Welch’s fascination with the medieval accounts of compulsive dancing. Welch connects this strange historical phenomenon with her own struggles, touching on themes of anxiety, panic, and and the experience of being overtaken by powerful emotion.

Learn More About Dancing Plagues

If you would like to learn more about the history of dancing plagues, I highly recommend watching the video version of the podcast I mentioned at the start of this article. It explores earlier outbreaks across Europe, how communities understood them, and the cultural forces that shaped these strange episodes.

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David Webb (Connect with me on LinkedIn)

Founder, All-About-Psychology.com

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