To Capture Hearts or Kill a King: The Spectacular Case of La Voisin
Updated: Jan 12
In Ep. 3 on my YT channel, I completed a book review of Judith Merkle Riley’s historical fiction The Oracle Glass. It’s a fun book set during the Affair of the Poisons, a fascinating event that occurred in late 17th century France. In short, it was an underground network of poisoners, renegade priests, and fortune tellers who assisted people with potions, spells, black masses, and murder by poison.
I can’t remember exactly when I first heard of the Affair of the Poisons (AOP), but I think it was while conducting research for a book. As these things always go, I started with one thing and fell down a rabbit hole of historical crime. Since the AOP is a complicated tale that includes a ton of people, I'll only discuss one of the women at the heart of the crime wave in this post. There are some other interesting figures connected to this story and I will discuss them in their own entries, but for now I want to look at the source, Catherine Montvoisin (née Deshayes), famously known as La Voisin. Reportedly, her black magic and poisoning network may have killed 1,000 people, though it’s believed she's responsible for as many as 2,500 deaths.
La Voisin was born around 1640. Apparently, she learned how to tell fortunes at the age of nine, but didn’t transform it into a money-making opportunity until later in life when her husband's jewelry and silk shop failed. Unwilling to live on the streets, she stepped in to support her family of six (including her husband, mother, and children).
She started by practicing chiromancy (palm-reading) and read the features of faces and heads (physiognomy). In addition to fortune-telling, she provided midwife services, including abortions and abortifacients. Though abortions were illegal at the time, she was able to complete them through a network of midwives who, for a fee, referred women to her.
As her popularity and wealth grew, she spent a great deal of money to provide the atmosphere that clients might expect of a fortune teller. For instance, she commissioned a special robe of crimson red velvet embroidered with gold eagles to perform in. The robe cost her 1,500 livres, which, in modern money, would amount to about $1,000 USD (give or take a few hundred—if I’ve managed to do the conversion correctly).
With her mystical robe, her air of fortune-telling mystery, and her ability to end an inconvenient pregnancy, by 1660, La Voisin was in high demand. She had attracted many important clients, many of whom were aristocrats close to King Louis XIV.
In 1665 or 1666, La Voisin was called for questioning by the priests of the Congregation of the Mission at the Saint Vincent de Paul's order about her divination, but she defended herself successfully by proclaiming the gift was from God. So, she was allowed to continue her fortune telling business. Though it's also likely her popularity and her fast climb up the social ladder had drawn their attention--especially since she was now close to people who were on intimate terms with King Louis XIV.
Like any good entrepreneur, she continued to search for ways to draw in more customers and money. During her consultations, she began to notice that most of her clients wanted someone to fall in love with them, or someone to die so they could inherit, or wished for their spouses to die so they could marry someone else. This opened an opportunity for La Voisin to take advantage of her clients’ desires, while generating a profit and growing her business.
She began by telling them that their wishes came true according to God's will. In order to influence His will, she recommended some action, such as visiting the church of a particular saint. Then she started to sell amulets and other "magical" objects or rituals like love powders made of powdered toad bones, mole teeth, Spanish fly, iron filings, human blood, embalming wax, and the dust of human remains.
For those clients wishing to make an inconvenient relative, spouse, or rival disappear, La Voisin provided fatal poisons. It wasn’t much of a stretch for the fortune-teller. Poisoning had become a common art and science by the 1660s, having been perfected, in part, by Giulia Tofana (whom I will definitely write about later), who worked in Italy only a few decades before La Voisin. As with her abortion and magic trades, La Voisin operated through a network of people to provide poisons for her clients.
When her clients felt God failed to provide enough, fast enough, or at all, they turned to Satan. La Voisin agreed to set up black masses so her clients could pray to Satan for their wishes to come true. Naturally, this was her most expensive service offered.
During some of these masses, a woman acted as an altar, upon which a bowl was placed: a baby was held above the bowl and its blood was poured into it. Whether the baby in question was actually killed on this occasion, was aborted, or whether the baby was already dead by natural causes (such as stillbirth), could vary.
As with her other services, she worked with several associates to help arrange and participate in her magic offerings, notably professional occultist, Adam Lesage, who assisted with the magic practice. However, she was also assisted by the occultist and defrocked Roman Catholic priest Étienne Guibourg and the French physicist and priest, Edme Mariotte, both of whom officiated the black masses.
The most important client of La Voisin's black mass was Madame de Montespan (I’ll write about her later, too), official royal mistress to King Louis XIV of France. Allegedly, Montespan hired La Voisin in 1667 to arrange a black mass. Adam Lesage and abbé Mariotte officiated, while Montespan prayed to win the love of the king. That same year, Montespan became the official mistress of the King. From that moment, she employed La Voisin whenever a problem occurred in her relationship with the King.
In 1673, when the King's interest in Montespan seemed to wane, Montespan again employed La Voisin to provide a series of black masses officiated by Étienne Guibourg. On at least one occasion, Montespan herself acted as the human altar during the mass. La Voisin also provided Montespan with an aphrodisiac, with which Montespan drugged the King.
In 1677, Montespan made it clear that if the King should ever abandon her, she'd have him killed. When the King entered into a relationship with Angélique de Fontangesin 1679 (the king was always entering into affairs), Montespan called for La Voisin and asked her to have both the King and Fontanges killed.
La Voisin hesitated, but eventually agreed. At the house of her colleague, Catherine Trianon, La Voisin, with her associates Trianon, Bertrand, and Romani (her daughter’s fiancé), concocted a plan to kill the King. Trianon was unwilling to participate and tried to discourage her, but Voisin refused to change her mind. The group decided to murder the King by poisoning a petition that would be delivered to his own hands.
On March 5, 1679, La Voisin visited the royal court in Saint-Germain to deliver the poisoned paper. That day, however, there were too many petitioners and the King didn't take their petitions. The assassination plot was foiled.
When she returned home, she handed the petition to her daughter, Marguerite Montvoisin, and asked her to burn it, which she did. The next day, she made plans to visit Catherine Trianon after mass to lay out another assassination plot against the King.
However, suspicion and fear of witches and poison was in the air. Around this same time, the death of the King's sister-in-law, the duchesse d'Orléans, had been falsely attributed to poison. Further, the crimes of Madame de Brinvilliers (whom I will definitely write about) and the arrest of the fortune teller and poisoner Magdelaine de La Grange happened in fairly quick succession and were still fresh in the public's mind. During this time, a riot broke out where people accused witches of abducting children for the black masses, and priests reported that a growing number of people were admitting to poisoning in their confessions.
In January 1679, fellow fortune-tellers and poisoners, Marie Bosse and Marie Vigoreaux, were arrested and, to deflect attention on their own crimes, informed police about the network of Parisian fortune tellers (including La Voisin) who distributed poison. Marie Bosse further claimed that La Voisin burned late-term aborted babies in her furnace and also buried them in her garden. Interestingly, Louis XIV ordered that La Voisin’s abortion business shouldn't be investigated. It's only supposition on my part, but I wonder if perhaps Louis had known women who had utilized La Voisin's abortion or midwife services and he didn't want to create a stir? At any rate, he shut down further investigation into that aspect of her business, so little is is known about the veracity of Bosse's accusations.
On March 12, 1679, La Voisin was arrested after mass outside Notre-Dame de Bonne-Nouvelle church--just as she was heading to her meeting with Catherine Trianon to plan the next assassination attempt. Several months later, on December 27, Louis XIV ordered that the entire network should be exterminated regardless of the rank, sex, or age. Soon after La Voisin's arrest, Marguerite Monvoisin (her daughter), Guibourg, Lesage, Bertrand, Romani and the rest of her network of associates were arrested.
Although a formal order allowed the use of torture to extract information, it was made clear that the order was not to be put in effect, so La Voisin was never "put to the question." The reticence to use torture was because there was some fear that she might reveal the names of influential people.
However, they used her alcoholism as leverage, keeping her drunk during her interrogations. Initially, she claimed to have referred all those clients wishing to buy poison to Marie Bosse. In March, however, she named Marguerite Leféron (the wife of a judge) and Francoise de Dreux (the wife of a parliament official) as clients. By the October 10, she admitted to selling poisons and magical services to several members of the royal court.
La Voisin denied ever meeting or serving Montespan. She did admit that “Paris is full of this kind of thing and there is an infinite number of people engaged in this evil trade.” Further, she refused to mention clients or that she had arranged or participated in black masses. In fact, her list of clients, the black masses, her connection to Montespan, and the murder attempt on the King didn't come to light until after her death, when it was revealed by her daughter and confirmed by the testimonies of her former associates.
On February 17, 1680, La Voisin was put on trial, and ultimately convicted of witchcraft and sentenced to execution by burning two days later. She was executed in public on the Place de Grève in Paris on February 22, 1680. On her way to her execution, she reportedly pushed away the priest and, when fastened on the stake, she desperately pushed away the hay which was piled up around her.
In July, her daughter, Marguerite Monvoisin, revealed her mother's connection to Montespan, which was confirmed by the statements of the other accused. This caused Louis XIV to eventually close the investigation, seal the testimonies and place the remaining accused outside of the public justice system by imprisoning them under an official, sealed order known as a lettre de cachet, thereby putting an end to the Affair of the Poisons. After hearing about this event, I kind of became obsessed with it. I immediately went and picked up the book below. In fact, I'm still reading that book because with in the first chapter I discovered another woman, Madame de Brinvilliers who catalyzed this entire event. So, falling down another rabbit hole, I began researching her. I then decided I want to tell the whole story in a limited series of books. That's the next project on my To Do list and I can't wait to get started!
For Further Reading:
Somerset, Anne. The Affair of the Poisons: Murder, Infanticide, and Satanism at the Court of Louis XIV. St. Martin's Press, (2004).