In 1509 he entrusted the reins of the Duchy to his mother and Hugues des Hazards, bishop of Toul, and followed Louis XII in his campaign in northern Italy, where he took part in the Battle of Agnadello of that year. After Louis' death, he went back to Italy and under Francis I, participating in the battle of Marignano (13–14 September 1515). However, called back home by problems in Lorraine, he was absent at the decisive battle of Pavia (1525), in which Francis was taken prisoner and his brother François, count of Lambesc, was killed.