Vendôme, César, duc de (sāzärˈ dük də väNdōmˈ) [key], 1594–1665, French general and politician; son of King Henry IV and his mistress Gabrielle d'Estrées. Legitimized in 1595, he was made duke of Vendôme in 1598, and also acquired Brittany through marriage. He rebelled against Marie de' Medici (1614–16) and against the duc de Luynes (1620) and was imprisoned (1626–30) for conspiring against Cardinal Richelieu. In 1641 he was forced to flee after being accused of plotting against Richelieu. Returning after Richelieu's death, he was exiled (1643) for conspiring against Cardinal Mazarin. However, he was reconciled, married his son to a niece of Mazarin's, and fought on the government side in the Fronde; he captured (1653) Bordeaux, and in 1655 he defeated a Spanish fleet at Barcelona.