Created royal lieutenant in 1347 by King Philip IV, Amaury was sent to Brittany with a small force and took La Roche-Derrien from the English in three days. In 1356, after being besieged at Romorantin in late August during the Chevauchée of the Black Prince, and ransomed, Amaury was taken prisoner at the Battle of Poitiers on the 19 September. Craon became one of the main captains of King John II of France and becomes Captain for Touraine, Anjou, Maine and Lower Normandy. Amaury is later influenced by the Poitou lords who are favourable to King Edward III of England and eventually joins them at the head of the Anglo-Poitevin coalition, facing Bertrand du Guesclin who is attempting to regain Poitou on behalf of King Charles V of France.