Educated at Jesuit schools, he intended to enter the priesthood, but at the last minute obtained from Louis XV an appointment as sub-lieutenant. He left France, according to the gossip of the time, because of a duel; served under the Elector Palatine; fought for Hungary against the Turks, and on the outbreak of the war of the Austrian Succession (1740) joined the army of the elector of Bavaria (who later became emperor under the name of Charles VII), displaying such bravery that he was promoted to the grade of lieutenant field-marshal.