Sorcery, Sex and Murder: The Parisian 'Affair of the Poisons' Had It All

By: Dave Roos  | 
Marquise de Brinvilliers
The Marquise de Brinvilliers was tortured with the "water cure" before she was executed for her role that ignited the Affair of the Poisons (oil on canvas by Jean-Baptiste Cariven). Didier Descouens/Wikimedia

In the 17th century, no monarch wielded as much power as King Louis XIV of France (1643-1715). From his opulent Palace of Versailles, the "Sun King" ruled over the wealthiest country in Europe, surrounded by a court of nobles anxious to win his favor and, in many cases, his affections.

"What you have in the court of Louis XIV is a lot of people jockeying for power, position and the ear of the king," says Lynn Mollenauer, a professor at the University of North Carolina Wilmington who specializes in this wild period of French history. For noblewomen, who had no real political power, one of the best ways to gain influence and financial security was in the king's bedroom.


"For women, the opportunities for behind-the-scenes power under Louis XIV were legion, because, well, the man got around," says Mollenauer. Louis XIV fathered 15 illegitimate children with his "official" mistresses alone.

When so much money and power is concentrated in one man and his royal court, people will do anything to gain an advantage or neutralize a rival, including dabbling in the dark arts. Paris in the 17th century was allegedly swarming with sorceresses, magicians and renegade priests who performed orgiastic "black masses" and peddled love potions and odorless poisons.

When a plot to poison Louis XIV was uncovered by Paris police, it triggered a full-blown "magic panic" that led to the arrests of prominent French aristocrats and their witchy accomplices. Tortured into confessions, dozens of people were thrown in prison, and 36 faced gruesome public executions.

The scandalous spectacle became known as the Affair of the Poisons.


The Case of the Killer Marquise

Charles Le Brun drew this portrait of the Marquise de Brinvilliers (left) on the day of her execution in 1676. She was beheaded for poisoning her father, Antoine Dreux d'Aubray (right) and others. Wikimedia

Like other moral panics in history, the Affair of the Poisons can be traced back to a lurid murder case that captured the public imagination.

French aristocrat Marie-Madeleine Marguerite d'Aubray, the Marquise de Brinvilliers, was wealthy and beautiful. She took a lover, a military captain named Godin de Sainte-Croix, but her father had Sainte-Croix arrested and thrown into the Bastille. While in prison, Sainte-Croix allegedly learned alchemy from a "master poisoner" named Egidio Exili.


When Sainte-Croix was released, he and the Marquise went on a poisoning spree, testing their increasingly toxic concoctions on unsuspecting hospital patients. When the odorless, tasteless poison was perfected (likely arsenic, says Molleneau), the Marquise used it to kill her father and two of her brothers, making her first in line to inherit the family's riches.

In 1675, the Marquise was accused of the murders and fled to England, the Netherlands and Belgium, where she was arrested. There she was tortured with "the water cure" and was forced to drink 2.4 gallons (9 liters) until she confessed.

The Marquise reportedly claimed that "half the people in [Paris] are involved in this sort of thing" and hinted at the existence of a ring of alchemists and sorceresses dabbling in the dark arts. Suddenly, every mysterious aristocratic death over the previous decade came under suspicion. The stage was set for the explosion of wild accusations during the Affair of the Poisons.

"The case of this beautiful noblewoman being found guilty of poisoning her family members in cold blood made it imaginable for the police, for the king and for the judges that these types of murders were widespread," says Mollenauer. "If somebody like the Marquise de Brinvilliers is capable of that, so too would other people."


The 'Criminal Magical Underworld' of Paris

After the Marquise was tortured and implicated others in the Parisian underworld, the police uncovered another plot to poison King Louis XIV. Wikimedia

Soon after the Marquise affair, the commander of the Paris police, Gabriel Nicolas de la Reynie, learned of an unrelated plot to poison King Louis XIV. La Reynie ordered his officers to leave no stone unturned in their investigation of Paris' "criminal magical underworld," as Mollenauer puts it.

There were indeed plenty of fortunetellers, magicians and self-proclaimed sorceresses plying their services in 17th-century Paris. Mollenauer says that these occult practitioners were "generalists," meaning they dabbled in everything from treating toothaches to locating hidden treasures.


If a woman went to the local sorceress complaining of a cruel and violent husband, she might go home with a few secret prayers to recite at mass. But if the prayers didn't work, says Mollenauer, the wife might return to the sorceress for something stronger, something that would make the "husband problem" go away for good.

Beginning with the Marquise case, rumors swirled around Paris that alchemists and witches had procured the ingredients for an odorless, tasteless, truly undetectable poison. They said it was extracted from toad venom and went by the name "succession powder," because it could quietly kill off your rivals for a handsome inheritance.

When La Reynie's men stormed the magic shops and alchemists, they confiscated vials of suspicious powders, bubbling cauldrons and foul ingredients for black magic including "blobs of hanged-man's fat, nail clippings, bone splinters, specimens of human blood, excrement, urine, [and] semen," according to one historian.

A Witch Hunt a Decade Before Salem

The most high-profile woman captured in the Affair of the Poisons was Catherine Deshayes Monvoisin, aka "La Voisin." 
The most high-profile woman captured in the Affair of the Poisons was Catherine Deshayes Monvoisin, aka "La Voisin." 

One of La Reynie's first arrests was a fortuneteller named Magdalene de la Grange, who was accused of faking a marriage to a wealthy Parisian lawyer and then poisoning him for his money. De la Grange was hanged and La Reynie was convinced that even more murderous "witches" were operating in Paris.

The next big arrest, says Mollenauer, was Marie Bosse, a well-connected fortuneteller who drunkenly boasted at a dinner party of getting rich from selling poison to plotting aristocrats. A shocked lawyer in attendance left an anonymous "denunciation" at the local church and "La Bosse," as she was known, was arrested and condemned to burn at the stake.

But the most high-profile conjurer captured in the Affair of the Poisons was Catherine Deshayes Monvoisin, aka "La Voisin." A talented sorceress and devout Christian, La Voisin's services were said to be in high demand, making her a rich "witch" indeed. Among her stronger "cures," La Voisin dealt in chemically induced abortions, poisons and love potions.

"I don't necessarily believe there was a plot to poison the king, but I am convinced there was a plot to slip him a lot of pretty disgusting love potions," says Mollenauer. "These were made out of things like iron filings, the blood of sacrificed infants (allegedly), and Spanish fly, which is an aphrodisiac."

Under torture, La Voisin gave up the names of dozens of fellow fortunetellers, magicians and sorceresses working in Paris, who in turn dropped the names of their clients, some with close ties to the crown, including the king's brother, Philip of Orleans.


Mistress of the 'Black Mass'

Athénaïs de Montespan was Louis XIV's favorite mistress. She was long assumed to have been involved in the Affair of the Poisons, but was never been positively implicated.  
Athénaïs de Montespan was Louis XIV's favorite mistress. She was long assumed to have been involved in the Affair of the Poisons, but was never been positively implicated.   Public Domain

Some of the most shocking accusations in the Affair of the Poisons were reserved for a woman named Athénaïs de Montespan, Louis XIV's favorite mistress. De Montespan bore seven children to the king, far more than any of Louis' official lovers.

When La Voisin was interrogated, she named de Montespan as one of her clients. La Voisin spun a sordid tale. She claimed to have provided de Montespan with the powerful love potions that kept the king under his mistress's spell for so many years. Mollenauer finds it plausible that Louis' mistresses would have resorted to drugging the king.


"The greater de Montespan's hold over the king," she says, "the greater her personal and familial benefits."

Far more disturbing, La Voisin claimed that de Montespan also participated with a defrocked priest in satanic "black masses" in which demons were conjured to attack their enemies. La Voisin was accused of offering her naked body as an altar upon which horrific rituals were performed, including infanticide.

The Affair of the Poisons lasted more than five long years, during which accused conspirators implicated others to save their necks. In the end, 36 people were executed and countless more were imprisoned or exiled.