The Dancing Plague of 1518 is one of the most bizarre and fascinating events in European history. Occurring in Strasbourg, Alsace (part of the Holy Roman Empire, now in modern-day France), it was a devastating outbreak of "choreomania"—a phenomenon where hundreds of people danced uncontrollably and seemingly against their will, leading to exhaustion, injury, and in some cases, death.
Here is a detailed explanation of the event, how it unfolded, and the modern theories surrounding its cause.
The Outbreak
The plague began in mid-July 1518 when a woman named Frau Troffea stepped into a narrow street in Strasbourg and began to dance fervently. There was no music, and she showed no signs of stopping. She danced until she collapsed from exhaustion, only to rest briefly and begin dancing again.
Within a week, about 34 others had joined her. By August, the epidemic had claimed around 400 victims. Observers noted that the dancers did not seem to be enjoying themselves; many were weeping, screaming in pain, and begging for mercy, yet their bodies continued to thrash, leap, and jig.
The Authorities' Disastrous Response
Unsure of how to handle the crisis, civic and religious leaders consulted local physicians. The doctors ruled out astrological alignments and supernatural causes, instead diagnosing the affliction as a "natural disease" caused by "hot blood."
According to the humoral medicine of the time, the only way to cure "hot blood" was to bleed the patient or force them to sweat it out. The authorities decided the dancers simply needed to "dance it out." In a move that severely backfired, the city council cleared public spaces, built wooden stages, and hired professional musicians and strong dancers to keep the afflicted moving.
Rather than curing the dancers, the music and spectacle acted as a contagion, drawing even more people into the fray. The physical toll was horrific. Dancers began dropping dead from heart attacks, strokes, and sheer exhaustion.
Realizing their mistake, the authorities reversed course. They banned music and public dancing, and the worst-afflicted victims were loaded onto wagons and taken to a shrine dedicated to St. Vitus, the patron saint of dancers and neurological disorders. There, they were given crosses, red shoes, and subjected to religious rituals. By early September, the epidemic finally began to subside.
What Caused the Dancing Plague?
For centuries, the cause of the 1518 Dancing Plague was a mystery. Modern historians and medical professionals have proposed two main theories to explain the phenomenon:
1. Ergot Poisoning (Ergotism)
Early modern historians suggested that the dancers had consumed bread made from rye infected with Claviceps purpurea, a toxic mold known as ergot. * The Theory: Ergot produces alkaloids that are pharmacologically related to LSD. Ergot poisoning (historically known as St. Anthony’s Fire) can cause terrifying hallucinations, violent twitching, and muscle spasms. * The Flaw: Most modern toxicologists and historians reject the ergot theory for this specific event. While ergotism does cause spasms, it also severely restricts blood flow to the extremities. A person suffering from ergot poisoning would quickly lose motor control and be entirely incapable of the sustained, vigorous aerobic exercise required to dance for days on end.
2. Mass Psychogenic Illness (Mass Hysteria)
Today, the most widely accepted explanation, championed by medical historian John Waller, is that the Dancing Plague was an extreme case of mass psychogenic illness (MPI), formerly known as mass hysteria. MPI occurs when a group of people under extreme psychological stress begin to manifest shared physical symptoms without a biological cause. * The Context of Extreme Stress: In 1518, Strasbourg was a city on the brink of collapse. The population was reeling from a series of disastrous harvests, severe famine, skyrocketing grain prices, and outbreaks of lethal diseases like syphilis and the sweating sickness. The psychological trauma of the populace was immense. * The Role of Belief (St. Vitus): The deeply pious and superstitious people of the region believed in a specific curse: that St. Vitus could punish sinners by forcing them to dance uncontrollably. * The Spark: When Frau Troffea began to dance, the distressed minds of the townspeople likely interpreted it as the St. Vitus curse. This cultural belief, combined with profound psychological trauma, caused others to fall into an involuntary dissociative state. Their minds essentially hijacked their bodies, forcing them to act out the very curse they feared. The musicians hired by the city only provided a rhythmic soundtrack that deepened the collective trance.
Historical Significance
The 1518 outbreak was not the only dancing plague in medieval Europe—similar outbreaks occurred in Germany, Switzerland, and Holland between the 14th and 17th centuries. However, the Strasbourg event is the most well-documented. It serves as a profound historical case study of how extreme psychological trauma, combined with deep-seated cultural and religious beliefs, can manifest in devastating physical ways.