Louis C%C3%A9sar, Count of Vexin

Louis Csar de Bourbon, Lgitim de France, Count of Vexin was a son of Louis XIV of France and his mistress Madame de Montespan. He was the Abbot of SaintDenis and of SaintGermaindesPrs.

Louis Csar, born at the chteau du Gnitoy, was the second son born to Louis XIV and Madame de Montespan. Named after Julius Caesar, his older brother Louis Auguste de Bourbon was named after Augustus and the later born Louis Alexandre de Bourbon was named after Alexander the Great.

Source: Wikipedia