Biography

Daughter of Catherine Deshayes, known as “La Voisin,” a poisoner and fortune-teller at the heart of the Affair of the Poisons under Louis XIV. Arrested after her mother's execution, she continued the revelations before the Chambre Ardente, implicating figures of the court.

Marie-Marguerite Deshayes

Marie-Marguerite Deshayes

6 min read

SocietyEarly ModernReign of Louis XIV, France of the Grand Siècle (late 17th century), during the Affair of the Poisons (1679-1682).

Frequently asked questions

Marie-Marguerite Deshayes, known as Monvoisin, was the daughter of the notorious poisoner La Voisin. The key thing to remember is that after her mother's execution in 1680, she became the main source of information for the Chambre Ardente (Burning Chamber). Her testimony detailed the network of poisons, the black masses of the abbé Guibourg, and implicated figures at court, including Madame de Montespan, the favorite of Louis XIV.

Key Facts

  • Daughter of Catherine Monvoisin (“La Voisin”), a central figure in the Affair of the Poisons
  • Her mother was burned alive on the Place de Grève on 22 February 1680
  • Arrested after her mother's execution, she gave new revelations to the Chambre Ardente
  • Her depositions fueled suspicions directed at people close to the king, including Madame de Montespan
  • Case investigated by the Chambre Ardente, created in 1679 and dissolved in 1682

Works & Achievements

Depositions before the Chambre Ardente (1680-1681)

Detailed testimony given after her mother's execution, forming a major source for understanding the poison network.

Implicating Madame de Montespan (1680)

Accusations targeting the king's favorite (black masses, poisoning attempts), which prompted Louis XIV to suspend the court.

Revelations about Abbé Guibourg and the black masses (1680)

Accounts of the sacrilegious rituals that fueled the investigation and the arrest of several priests and accomplices.

Description of the trade in powders and potions (1680-1681)

Explanations of how poisons and brews were made and sold, revealing the practices of the family household.

Testimony about the court clientele (1681)

Identification of the great ladies and figures who came to consult La Voisin, broadening the inquiry into aristocratic circles.

Anecdotes

On 22 February 1680, her mother La Voisin was burned alive on the Place de Grève. The Marquise de Sévigné recounts in a letter that she cursed, pushed away the straw of the pyre, and died “impiously.” Marguerite, already imprisoned, then became the chief heir to her mother's secrets.

Before the Chambre Ardente, Marguerite recounted that black masses had allegedly been celebrated by the abbé Guibourg on the bare belly of a great lady to win the king's favor. Her testimony directly implicated Madame de Montespan, the favorite of Louis XIV, which terrified the court.

Marguerite described the trade in “inheritance powders” that her mother sold: poisons disguised as remedies or love potions, bought by ladies eager to inherit or to rid themselves of a husband. These revelations exposed an entire Parisian network of fortune-tellers and poisoners.

Because of her accusations against the royal favorite, Louis XIV himself suspended the hearings of the Chambre Ardente in the autumn of 1680. The king preferred to smother the scandal rather than allow those close to the throne to be tried publicly.

Many of those accused in the affair, including the holders of the most dangerous secrets, were never tried: they were locked away for life in fortresses by lettres de cachet, sometimes in chains, so that they could no longer speak. In 1709, the aged Louis XIV had the bundles of the case file burned to erase the compromised names.

Primary Sources

Letter from Madame de Sévigné to Madame de Grignan (23 February 1680)
So this is the death of La Voisin, famous for her crimes and her impiety. […] she swore a great deal and pushed away the straw five or six times, and at last the fire took her.
Archives of the Bastille (records of the Chambre Ardente), ed. François Ravaisson (1680-1681)
Interrogations and depositions of the Monvoisin girl, in which she reports the names of the people who came to buy powders and seek conjurations at her mother's house.
Memoirs and notes of Nicolas de La Reynie, lieutenant general of police (1679-1682)
A collection of documents from the Affair of the Poisons in which the magistrate records the confessions concerning the sacrifices, the masses, and the poisons prepared in the house on the rue Beauregard.
Royal Edict on Poisons and Diviners (July 1682)
An ordinance of Louis XIV regulating the sale of poisonous substances by apothecaries and forbidding diviners and magicians from practising their false science.

Key Places

House on rue Beauregard, Paris

La Voisin's home in the Paris faubourg, where divination consultations, powder sales, and rituals took place. Marguerite grew up here, at the heart of the network of poisoners.

Place de Grève, Paris

The square for public executions in front of the Hôtel de Ville, where La Voisin was burned alive on 22 February 1680. The execution marked the turning point of the affair for Marguerite.

Arsenal of Paris (Chambre Ardente)

Seat of the special tribunal created by Louis XIV to try the Affair of the Poisons. Marguerite was interrogated here and gave her testimony before La Reynie.

Keep of Vincennes

A royal fortress used as a prison for those accused in the Affair of the Poisons. Many keepers of secrets were locked up here without trial by lettre de cachet.

Palace of Versailles

Residence of the court of Louis XIV and of the royal favorite Madame de Montespan, whose name was uttered in Marguerite's testimony. The scandal threatened the very heart of power.

Liens externes & ressources

Œuvres

Dépositions devant la Chambre ardente

1680-1681

Mise en cause de Madame de Montespan

1680

Révélations sur l'abbé Guibourg et les messes noires

1680

Description du commerce des poudres et philtres

1680-1681

Témoignage sur la clientèle de cour

1681

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See also