Gilberte Pascal Périer was born in Clermont-Ferrand in the French province of Auvergne to a distinguished family. Her father Étienne Pascal, a lawyer, served as president of the Cour des Aides, a provincial tax court. Her mother Antoinette Begon, who died in 1626, came from a family of French diplomats and judges. Her younger siblings were Blaise Pascal and Jacqueline Pascal. Their father educated his children at home, stressing mathematics and philosophy as well as literature and history. In 1631, the family moved to Paris, where she began running the household at age 15. In 1641, she married Florin Périer, a councillor of the Cour des Aides, with whom she had at least four children, including Marguerite Périer, who became a memoirist. During a visit to her father and siblings living in Rouen in 1646, she converted to the controversial Jansenist movement. In 1648, her husband conducted one of the most famous experiments of the Scientific Revolution, on atmospheric pressure, on top of the Puy-de-Dôme, the highest mountain in the Auvergne, on behalf of Blaise Pascal, who was ill. She frequented intellectual gatherings and was known for her eloquent conversation. She wrote a biography of Blaise called La Vie de Monsieur Pascal, and of her sister, Vie de la Soeur Saint-Eustache. She assisted in the posthumous publication of her brother's most influential work, Pensées (1670).