During the Battle of Britain, Hitler gave the German armed forces ("Wehrmacht") a directive (Directive No. 16) that ordered provisional preparations for invasion of Britain. This operation was codenamed Operation Sea Lion ("Unternehmen Seelöwe"). Before this could be carried out, air superiority or air supremacy was required. The "Luftwaffe" was to destroy the RAF in order to prevent it from attacking the invasion fleet or providing protection for the Royal Navy's Home Fleet, which might attempt to prevent a landing by sea. On 1 August Hitler gave the "Luftwaffe"s commander-in-chief, "Reichsmarschall" (Empire Marshal) Hermann Göring and the "Oberkommando der Luftwaffe" (High Command of the Air Force) a directive (Directive No. 17) to launch the air assault.