Brinvilliers, Marie Marguerite, Marquise de, the daughter of Dreux d'Aubray, a respectable French official, was born in 1630. She married the Marquis de Brinvilliers, but soon left him for a lover, Gaudin de Sainte-Croix, an officer of cavalry. The latter had learned from an Italian the art, then very fashionable, of preparing secret poisons, which probably had arsenic as their base. He communicated this knowledge to his mistress, and together they got rid of her father, her two brothers, and her sister, with a view to obtaining their property. In 1670 Sainte-Croix killed himself whilst experimenting, and his papers revealed the crime. Madame de Brinvilliers fled to Liege, and took refuge in a convent, but a police-officer in the guise of an abbe contrived to bring her back to Paris, where, after terrible tortures, she was beheaded in 1676.