In February 1679, a fortune teller named Catherine Deshayes, known throughout Paris as La Voisin, walked into the royal court of King Louis XIV with a poisoned petition folded in her hands. Her plan was simple: the king would take the paper, the poison would seep into his skin, and the Sun King would die. But too many courtiers crowded around him that day, and she could not get close enough to deliver it. A week later, before she could try again, she was arrested.
At the time, the police had no idea they had just caught a woman who had plotted to kill the king. They were rounding up suspected poisoners in connection with a scandal that had been rotting the court for years. La Voisin had not always moved in such dangerous circles. Born in Paris around 1640, she grew up poor and with little education.
As a girl, she told fortunes on the streets, claiming she had learned the art at the age of nine. Her predictions were often accurate, and the talent she considered a gift from God made her a name in the city. Around the age of twenty, she married Antoine Monvoisin, a struggling businessman who tried his hand at silk trading and ran a small jewelry shop with little success. To support her family, La Voisin expanded into midwifery.
But delivering babies paid far less than abortion, which was illegal and therefore far more profitable. She built a network of providers and used her midwife practice as a front. When late-term fetuses needed disposal, she burned them in her furnace and buried the remains in her garden. She attended Mass regularly despite her work, and in 1665, when a priest questioned her fortune telling, she convinced professors at the Sorbonne that her powers came from God.
She was released and continued as before. By the late 1660s, her clientele included many of the French aristocracy. She dressed in finer clothes, most notably a crimson velvet robe embroidered with golden eagles that cost 1,500 livres. She hosted parties where she played the violin, took wealthy lovers, and freely mixed with the upper classes.
Her fortune telling had revealed a pattern: clients wanted love, they wanted inheritances, and they wanted spouses dead. She began offering more than predictions. She created amulets, love powders, and magical objects. She organized black masses in the catacombs near her house, rituals where a naked woman served as the altar, a chalice rested on her stomach, and a priest poured blood into the cup while those present prayed to Satan.
Whether the blood came from living or dead infants is unknown, but she had no shortage of children, given her abortion business and her practice of taking unwanted newborns off the hands of poor women. Eventually, she stepped over the final line. She began selling poisons to clients who wished to end someone’s life, and she built a network of providers working under her. This decision would haunt her.
In 1667, she was hired by Madame de Montespan, a member of the king’s court who wanted Louis XIV to fall in love with her. Montespan used aphrodisiacs, seduction, and black masses. It worked. By July of that year, she became the king’s official mistress.
But by 1673, the king’s interest began to fade. Montespan returned to La Voisin, desperate to keep his love. By 1679, the king had moved on to another lover, Angélique de Fontanges. Furious, Montespan asked La Voisin to poison both Fontanges and the king.
La Voisin hesitated but eventually agreed. Her arrest came before she could finish the job. The investigation that caught her had begun in 1677, when a fortune teller named Magdelaine de La Grange was arrested on charges of forgery and murder. She bargained for her freedom by offering information about crimes involving the royal court.
The chief of police, Gabriel Nicolas de La Reynie, was tasked with rooting out all poisoners. The investigation spread to accusations of witchcraft, murder, child abduction, and Satanic ritual. La Voisin’s enemy, Marie Bosse, another fortune teller and alleged witch, was arrested and pointed to La Voisin as the mastermind behind the poison network. La Voisin was imprisoned and interrogated.
The police knew she drank heavily and kept her supplied with alcohol, so she was often drunk during questioning. At first she denied everything, claiming that any client seeking poison was referred to Marie Bosse. But by October, she admitted to selling poison and magical services to several nobles, including members of the royal court. When pressed for more names, she replied that Paris was full of such people and that an infinite number were engaged in the evil trade.
Her confessions were not enough for the death penalty, so her accusers focused on her abortion services. They claimed she injected syringes into pregnant women, aborted fetuses, burned the bodies, and buried them in her garden. She denied it all. She feared being questioned about her visits to the royal court, but the police knew nothing of the plot to kill the king, nothing of the black masses, and nothing of her connection to Montespan.
On February 17, 1680, she was tried and convicted of witchcraft and sentenced to be burned at the stake. Before her execution, she was reportedly tortured by having her legs crushed, yet a witness described her moving freely and appearing healthy shortly before her death. She did not confess. On February 22, 1680, La Voisin was burned alive in public on the Place de Grève.
On the way to the stake, she desperately pushed away the hay piled around her. The full truth only emerged after her death. Her daughter disclosed the list of clients, the black masses, the connection to Montespan, and the attempt to poison the king. Her former associates confirmed the account.
Estimates of the number of people she was involved in killing range from one thousand to twenty-five hundred through her network of abortion providers, black masses, and poisons. The woman who once claimed her fortune telling was a gift from God had become one of the most prolific killers in French history, and only her death revealed the scale of the darkness she had hidden beneath her crimson robe.