Johann Joseph Gassner – Exorcist Healer

In late eighteenth century southern Germany, in the middle of the Age of Enlightenment, a portly, balding catholic priest by the name of Johann Joseph Gassner shot to fame by claiming to heal thousands through the power of exorcism.

Treating patients from all walks of life including princes and peasants, the unassuming Father Gassner staged bombastic rituals in front of enthralled crowds, triggering a German catholic revival as well as provoking bitter responses from sceptical critics. In the face of eye-witness testimony and heated religious debate, scientific thinkers attempted to explain these seemingly miraculous cures through a strange new power dubbed ‘animal magnetism’ and engaged in some of the first discussions of the placebo effect in medicine.

Demons and Disease

‘[The Ancients believe] all things are full of demons, and that they are able to invade men and drive them mad.’

– Johann Salomo Semler

Johann Joseph GassnerBorn in the village of Braz in the Vorarlberg region of western Austria in 1727, Johann Joseph Gassner began his religious training with the Jesuit order in Prague before starting his own secular career in 1750. It was during his time as a priest in Klösterle however, that he discovered his power for healing. After suffering acute headaches and fainting spells for many years, from which he reported learned doctors could offer no relief, Gassner concluded that his maladies were being caused by the devil, and therefore decided to exorcise himself.

The belief that evil spirits, or the devil, lay behind human illness stretches far back into antiquity. Yet by the eighteenth century, reformed, protestant thinkers, such as Johann Salomo Semler, had begun to question the Christian basis of such ideas. Despite this, belief in medically meddling spirits remained strong and when Gassner’s self-exorcism seemed to work, he resolved to spend the next decade perfecting this method of healing.

Beginning with a ‘test exorcism’, Gassner would first address the demon in Latin, a language he assumed his lay patients would be unable to understand, before ordering it to move around the person’s body, inducing them to perform strange acts and assume unusual positions. One recorded example states that Gassner made one man suffering from ‘St. Vitus’ dance’ (a condition known today as Sydenham’s chorea), first hop around the room three times and then suffer a fit upon command, falling to the floor, thrashing and ‘bellowing like an ox’.

Between 1767-1769, Gassner recorded in his diary that he cured 132 people including 13 epileptics, 29 cripples, and even one dead woman. The priest did not exorcise everyone who came to him however, only those whose illness he believed to be caused by the devil. People deemed to be suffering a ‘natural illness’, against which exorcism would prove of little use were dismissed without cure, as were those of ‘small or reluctant faith’. Nevertheless, by 1774, Gassner’s reputation had grown sufficiently that he embarked upon a healing tour of southern Germany.

Demons and Doctors

‘If all the illnesses that this priest describes originate from the devil, and if they can be treated by exorcisms, then bid our physicians farewell’

– Report from a Bavarian newspaper, 1774

Johann Joseph GassnerAs Johann Joseph Gassner’s fame grew, so did the number of people who sought his help. In 1775, he is reported to have cured 125 people in the last half of June alone, whilst his supporters place the total number of patients healed in the tens of thousands.

Around the same time as Gassner’s career was reaching its height, another Austrian-based healer was making a reputation for himself with a new therapy rooted in the young science of magnetism. In 1774, physician Franz Anton Mesmer found that he could manipulate strange forces within his patients by moving magnets around their bodies. This practice had made Mesmer a celebrity in Vienna and when he discovered that he could achieve the same effect through touch and mental concentration alone, the doctor concluded that he was healing people via a force he called ‘animal magnetism’, which he believed all living creatures possessed.

Noting the similarities between his technique and Gassner’s, Mesmer determined that the priest was in fact healing through animal magnetism without knowing it. Gassner’s talk of possession, exorcisms, Jesus and the devil could therefore be dismissed as superstitious nonsense.

Although Mesmer and his theory of animal magnetism were ultimately rejected by the eighteenth century scientific community, this attack upon Gassner illustrates both the growing concern amongst doctors at the priest’s success, and their attempts to find a rational, scientific explanation for it.

Sometimes however, Gassner would demonstrate abilities medical professionals were simply unable to explain. In Ellwangen in 1775 for example, the priest was apparently able to make his patient’s symptoms manifest and then disappear upon command, so that ‘the pulse in the right arm… [became] weak and barely detectable, but in the left arm… [became] strong and fast.’ Interestingly, the witnesses state that Gassner continued to demonstrate this until the patient became ‘convinced of the origin of his illness’ and the priest’s power over it. Gassner would then teach his patient to ‘help himself in future’, commanding the sickness to return again and charging the patient to make the pain go away. This process was repeated until the patient had it mastered.

Writing after the event, Swiss physician Dr Johann Georg Zimmermann reasoned that Gassner’s cures worked through the power of suggestion, a charismatic authority that gave him ‘mastery over the imagination and nerves of ordinary people’. Such conclusions certainly fit with Gassner’s inability to cure those of ‘small or reluctant faith’ and suggest his success may have been the result of a placebo effect.

Exorcism and the Enlightenment

‘Far be it from us to accept as dogma that the devil can physically enter people… [and] that the devil makes them sick. We must refute all these things, root them out like weeds that smother religion’

 – Johann Salomo Semler

ExorcismWith an increasing number of patients attesting that Father Gassner’s exorcisms produced real and lasting results, a cult of sorts began to grow up around the catholic priest. Small copper-plate engravings depicting Gassner’s image were sold to crowds in the towns he visited, whilst his ‘printed blessings’ adorned the rooms of pious and superstitious people across southern Germany.

Not everyone believed Gassner’s fame and influence was a good thing however, nor were the priest’s enemies limited to competitively minded physicians. In the late eighteenth century, memories of the witch trials which had ravaged Europe just a century before were still strong, and the Catholic Church as a whole was wary of encouraging exorcism and talk of demonic possession. To many modern theologians, Gassner’s dramatic public exorcisms began to look increasingly dubious, even dangerous.

By late 1775, a growing number of intellectuals and powerful holy men had turned against Gassner, who now found himself barred from entering several German territories. Eventually even the Vatican could no longer ignore the controversy surrounding these events, and in 1776 Pope Pius VI officially condemned Gassner’s healing practices as false and sensationalist, ordering the priest to cease exorcising immediately. Finally, at the command of Emperor Joseph II of the Holy Roman Empire, Father Johann Joseph Gassner was banished to the obscure province of Pondorf in northern Austria, where he died in 1779.

Despite his rather ignoble end, the controversy surrounding Johann Joseph Gassner’s exorcisms lived on and continued to be debated in Germany long after his death. The fervour with which people from all classes had embraced his particular blend of religious healing is unparalleled in eighteenth century Europe, making the Austrian priest one of the most important and least well-known figures of the Enlightenment.

Ancient MedicineLiam A Faulkner

Liam is the author of Ancient Medicine: Sickness and Health in Greece and Rome.

See also Liam’s articles on The Plague of Athens, Hippocrates and the Hippocratic Oath and Herophilus and Erasistratus: The ‘Butchers’ of Alexandria