The possessions at Louviers (Normandy, France), similar to those in Aix-en-Provence, occurred at the Louviers Convent in 1647. As with both the Aix case and its later counterpart in Loudun, the conviction of the priests involved hinged on the confessions of supposed possessed demoniacs.
The source for information on the subject is in large part a book entitled Histoire de Magdelaine Bavent, Religieuse de Louviers, avec son interrogatoir, etc. (History of Madeleine Bavent, a Nun of Louviers, together with her Examination, etc.), 4to: Rouen, 1652 from an interview with Madeleine Bavent by an Oratorian.
Accusations
Madeleine Bavent was born at Rouen in 1607. An orphan, at the age of twelve she was bound as an apprentice to a linenworker, whose business was dependent on the Church's patronage. According to historian Jules Michelet, the confessor of the establishment, probably drugged the apprentices with something like Atropa belladonna and led them to believe that he was conducting taking them to a "Sabbath". He had his way with three of them, and Madeleine, at fourteen, was the fourth.
At the age of sixteen, she entered a Hospitaller convent that had been established in the woods outside Louviers. Michelet says that the elderly supervisor, Father David, "was an 'Adamite', preaching the nudity Adam practised in his innocence", but that Madeleine declined "to submit to this strange way of living' and incurred the displeasure of her superiors. She lived apart from the rest of the community, having been given the job of tourière -the nun who attends to the turning-box of a convent, by means of which communication is kept up with the outside world. Upon Father David's death, he was succeeded as curé by Mathurin Picard, who appointed her sacristan, pursued her with amorous intentions and magic potions, and made her pregnant.
Sister Madeleine Bavent was 18 years old in 1625; the initial possession victim, she claimed to have been bewitched by the now deceased Picard, the nunnery's former director, and Father Thomas Boulle, the vicar of Louviers. Her confession to authorities claimed that the two men had abducted her and taken her to a witches' sabbat. There, she was married to the Devil, whom she called "Dagon", committed sexual acts with him on the altar, and that two men were allegedly crucified and disemboweled as these acts took place.
Madeleine's confession prompted the investigation, which found that other nuns reported having been brought to secret sabbats by Picard and Boulle, where sexual intercourse with demons, particularly Dagon, took place. These confessions were accompanied by what investigators believed were classic signs of demonic possession: contortions, unnatural body movements, speaking in tongues (glossolalia), obscene insults, and blasphemies.
Beyond mere symptoms of possession, the body of Sister Barbara of St. Michael was said to be possessed by a specific demon named Ancitif.
Exorcisms
As in the Loudun possessions a decade prior, the exorcisms at Louviers were a public spectacle. Nearly every person present at the exorcisms was questioned by the inquisitors, and the entire town of Louviers began exhibiting symptoms of hysteria as the cries of the nuns undergoing exorcism rose with the screams of Father Boulle, who was tortured at the same time; Mathurin Picard had died previous to the public display.
Father Bosroger recorded the proceedings, which he would publish in 1652. In his account, nuns were said to confess further evidence against Picard and Boulle. In addition to tempting them into sexual acts, Satan (supposedly in the form of Picard and Boulle) had also tried leading the nuns down the road of heresy. Appearing to the nuns as a beautiful angel, the Devil engaged them in theological conversations so clever that they began to doubt their own teachings. When told that this was not the same information they had been taught, Satan replied that he was a messenger of heaven who was sent to reveal fatal errors in what was otherwise accepted dogma.
Signs of possession continued throughout the exorcisms. One witness wrote that a nun "ran with movements so abrupt that it was difficult to stop her. One of the clerics present, having caught her by the arm, was surprised to find that it did not prevent the rest of her body from turning over and over as if the arm were fixed to the shoulder merely by a spring."