Though in 1914, French naval doctrine was dominated by Mahan's theory of sea power, the course of World War I changed ideas about the place of the navy. The refusal of the German fleet to engage in a decisive battle, the Dardanelles expedition of 1915, the development of submarine warfare, and the organization of convoys all showed the French Navy's new role in combined operations with the French Army. The Navy's part in securing victory was not fully understood by French public opinion in 1918, but a synthesis of old and new ideas arose from the lessons of the war, especially by Admiral Raoul Castex (1878–1968), who synthesized in his five-volume Théories Stratégiques the classical and materialist schools of naval theory. He reversed Mahan's theory that command of the sea precedes maritime communications and foresaw the enlarged roles of aircraft and submarines in naval warfare.Martin Motte, "L'epreuve des Faits: ou la Pensee Navale Française face a la Grande Guerre", Revue Historique Des Armées 1996 (2): 97–106. .
