Charles IX sent an army against Béarn under Antoine de Lomagne, baron of Terride in 1569, during which Antoine de Gramont retired to Bidache since he was unable to resist it. After the count of Montgomery's capture of Orthez, Antoine de Gramont met him but was unable to come to an agreement regarding the lieutenant-generalcy of Navarre and so retired to his château. He was present at Henry of Navarre's marriage to Marguerite de Valois in Paris and Charles IX put him under his protection, thus saving him from the St. Bartholomew's Day massacre. He renounced Protestantism and remained a Catholic until his death.