Crillon's service with Spain was further rewarded in 1783 with the title of Knight of the Golden Fleece. He was appointed captain-general of the kingdoms of Valencia and Murcia. He remained in Spain during the years of the French Revolutionary Wars, writing his memoirs ("Memoires militaires de Louis de Berton des Balbes de Quiers"), published in 1791. He took no part in the War of the Pyrenees (1793–95) between Spain and revolutionary France, but played a significant role in agreeing the peace that terminated the conflict. He died in Madrid in June 1796.