1544年より従兄のロレーヌ公フランソワ1世の軍隊に入り、1545年のブローニュ包囲戦(仏: Siège de Boulogne)に加わる。1550年に父を亡くすと、兄はギーズ公爵の称号を代襲し、クロードはブルゴーニュ総督職を継ぎ、オマール公爵領を継承した。
オマール公Aumaleinherited the governorship of en:Burgundy from his father, and the duchy of オマール公Aumalefrom his brother who assumed the titles of Guise.
Carroll, Stuart (1998). Noble Power During the French Wars of Religion: The Guise Affinity and the Catholic Cause in Normandy. Cambridge University Press
Carroll, Stuart (2005). Noble Power during the French Wars of Religion: The Guise Affinity and the Catholic Cause in Normandy. Cambridge University Press
Carroll, Stuart (2009). Martyrs and Murderers: The Guise Family and the Making of Europe. Oxford University Press
Durot, Éric (2012). François de Lorraine, duc de Guise entre Dieu et le Roi. Classiques Garnier
George, Hereford Brooke (1875). Genealogical Tables Illustrative of Modern History. Oxford at the Clarendon Press
Shimizu, J. (1970). Conflict of Loyalties: Politics and Religion in the Career of Gaspard de Coligny, Admiral of France, 1519–1572. Geneva: Librairie Droz
Wellman, Kathleen (2013). Queens and Mistresses of Renaissance France. Yale University Press