The French Navy (, "national navy"), informally , is the maritime arm of the French Armed Forces. Tracing its roots back to 1624 it is one of the world's oldest naval forces and historically played a key part in establishing the French colonial empire. Since the early foundings, its roles have been defined as maintaining intelligence, protecting populations, preventing crises, intervening wherever necessary to reestablish peace, and dissuading any threats against vital French interests. The Marine nationale consists of four branches: the Force d'Action Navale, the Forces Sous-marines, the Aéronavale and the Fusiliers Marins (including Commandos Marine). As a blue-water navy the Marine nationale operates a wide range of fighting vessels, including a nuclear-powered aircraft carrier, nuclear-powered submarines, frigates, patrol boats and support ships. The French Navy does not use prefixes of the names of its ships (such as the Royal Navy uses HMS, for instance). Foreign commentators sometimes use the prefixes "FS" (for "French Ship") or FNS (for "French Navy Ship"); these are not official, however.