"César de Bourbon, Légitimé de France (3 June 1594 – 22 October 1665) was the illegitimate son of Henry IV of France and his mistress Gabrielle d'Estrées, and founder of the House of Bourbon-Vendome. He held the titles of 1st Duke of Vendôme, 2nd Duke of Beaufort and 2nd Duke of Étampes, but is also simply known as César de Vendôme. Through his daughter, Élisabeth de Bourbon, César was a great-great-great-grandfather of Louis XV of France." - (en.wikipedia.org 06.07.2021)