In July 1518, a woman named Frau Troffea stepped into the streets of Strasbourg and began to dance. She didn't stop for days. Within a week, dozens joined her. By the end, hundreds had danced themselves to exhaustion, injury, and in some cases, death.
This was the Dancing Plague of 1518 — and it remains one of history's most baffling mass psychogenic episodes.
What Happened
On a hot July day, Frau Troffea began dancing fervently in a narrow Strasbourg street. She continued for four to six days without rest. Within a week, thirty-four others had joined. By August, the epidemic had grown to around 400 dancers.
Accounts from physicians of the time — including the eminent Paracelsus — describe people dancing wildly and uncontrollably, screaming of terrifying visions. Some danced until their feet bled. Others collapsed from heart attacks, strokes, or sheer exhaustion. Historical records note several deaths.
The city council, alarmed, took what seemed like a sensible approach: they hired musicians to play alongside the dancers, believing the afflicted would dance themselves cured. They also built a wooden stage and brought in professional dancers, thinking that controlled dancing might help. Instead, it encouraged more people to join.
The Theories
Mass Psychogenic Illness
The leading modern explanation is mass psychogenic illness (also called mass hysteria) — a phenomenon where physical symptoms spread through a population without an organic cause. It's the same mechanism behind outbreaks of laughing, fainting, or tics in schools and communities.
Strasbourg in 1518 was ripe for it. The region had endured years of famine, crop failure, and the lingering trauma of diseases like syphilis. The population was superstitious, deeply religious, and terrified of divine punishment. A woman named St. Vitus (Sankt Vitus) was believed to curse people with compulsive dancing — and, ironically, praying to him was considered the cure.
Once the idea of a "dancing curse" took hold, the stress and belief could trigger genuine involuntary movement in others. It was a feedback loop: the more people danced, the more credible the curse seemed.
Ergotism
Another theory points to ergotism — ergot fungus grows on damp rye grain and contains compounds chemically related to LSD. Ergot poisoning causes convulsions, hallucinations, and twitching that could be mistaken for dancing. It was common in medieval Europe and was known as St. Anthony's Fire.
The problem? Ergot poisoning typically causes convulsions and spasms, not coordinated dancing. And it's not contagious. The pattern of the 1518 outbreak — spreading person-to-person over weeks — doesn't fit a foodborne toxin.
Religious and Social Factors
Paracelsus, who visited Strasbourg in 1526 (eight years later), dismissed demonic possession and instead diagnosed it as a "natural disease" caused by psychological factors. He prescribed moderation, rest, and "purging" — about as close as a Renaissance physician could get to prescribing therapy.
Modern psychiatrists point out that the dancing plague occurred amid a perfect storm: starvation, disease, religious anxiety, and a cultural belief system that made hysterical contagion possible.
Legacy
The Dancing Plague of 1518 wasn't unique. Similar outbreaks occurred in Germany, Italy, and Madagascar as recently as the 1840s (the Madagascar "dancing mania" involved the Antandroy people dancing for days, sometimes falling into trances). But 1518 is the best-documented case.
It's a stark reminder that the mind can produce very real, very physical symptoms — especially under stress. And that sometimes, the most terrifying thing isn't a demon or a poison. It's the stories we tell each other.
Sources
- John Waller, The Dancing Plague: The Strange, True Story of an Extraordinary Illness (Sourcebooks, 2009)
- Paracelsus, On the Diseases That Deprive Man of Reason (1526)
- Contemporary Strasbourg municipal records (1518)
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