Catherine Trianon, née Boule, called La Trianon (1627 - 6 May 1681), was a French fortune teller and poisoner, one of the accused in the famous Poison Affair. She was actively involved in the attempted assassination of king Louis XIV of France in 1679.
Catherine Trianon was a widow and fortune teller. She was one of the most important associates, as well as a personal friend and confidante, of La Voisin. She managed her business with her partner, La Doddée, who was also her lover in a homosexual relationship. Trianon was described by her colleagues as very well educated, and at her house was later found 25 manuscript for works about occultism. Her reception room contained a human skeleton, officially there as a pious reminder of mortality. In 1679, Madame de Montespan commissioned La Voisin to murder the monarch. It was at the house of Trianon that La Voisin planned the conspiracy with the help of her lovers, Bertrand and Romani. Trianon tried to convince Voisin to give up the plans, even making up a horoscope to warn her that it would be a mistake, but did not succeed. The group decided that the king should be poisoned by a petition. La Voisin failed with the first attempt on 5 March; the 12 March, she had planned a meeting with Trianon to plan the next attempt, when she was arrested. Voisin's arrest was followed by that of Trianon in May.
Upon her arrest, authorities found 25 "manuscript volumes on the occult sciences" in her house.
In August 1680, after the execution of La Voisin in February, the connection between La Voisin and Montespan and the plan to assassinate the king was revealed by her daughter Marguerite Monvoisin, who in 9 October also confirmed the August statements by Adam Lesage of child sacrifice at the black masses. After her statements about Montespan and child sacrifice were confirmed by Francoise Filastre 1 October and Etienne Guibourg in 10 October, Trianon, who had been personally involved in the attempt, also confirmed the statement. Catherine Trianon committed suicide in Château de Vincennes.
Catherine Trianon is given a fairly large portrayal in a novel by Judith Merkle Riley: The Oracle Glass (1994)
- Princes and Poisoners Or Studies of the Court of Louis XIV by Frantz Funck-Brentano
- The Affair of the Poisons: Murder, Infanticide, and Satanism at the Court of Louis XIV by Anne Somerset (St. Martin's Press, 2003) ISBN 0-312-33017-0
- 1679-1682, l'affaire des poisons by Arlette Lebigre