César d'Estrées  César d'Estrées (5 February 1628 – 18 December 1714) was a French diplomat and cardinal. Estrées was born and died in Paris. He was the son of Marshal François Annibal d'Estrées and nephew of Gabrielle d'Estrées, mistress of King Henri IV. His brother was Marshal Jean II d'Estrées. Estrées was abbot of the Abbey of Saint-Germain-des-Prés, Duke-Bishop of Laon and a cardinal. He was also French ambassador in Rome and Spain, commander in the Order of the Holy Spirit and a "pair de France". He was elected member of the Académie française in 1658 (Seat 9).