Isabeau de Thouars
Isabeau de Thouars (died 1397) was a daughter of Louis I, Viscount of Thouars, and Joan II, Countess of Dreux. Her first husband, the marshal of France Guy II de Clermont-Nesle, was killed at Mauron in 1352. In 1356 she married Ingelger I d'Amboise, by whom she had two sons, Pierre II and Ingelger II.
Her third husband was Guillaume d'Harcourt. When her sister Péronnelle died in 1397, Isabeau's Amboise sons carried on the Thouars succession, with Pierre II ruling the viscounty until 1426.