when did the war department change its name
United States Department of War The War Department existed from August 7, 1789[1] until September 18, 1947, when it split into Department of the Army and Department of the Air Force and joined the Department of the Navy as part of the new joint National Military Establishment (NME), renamed the United States Department of Defense in 1949.
Military history of the United States during World War II During the war, over 16 million Americans served in the United States Armed Forces, with 405,399 killed in action and 671,278 wounded.[3] There were also 130,201 American prisoners of war, of whom 116,129 returned home after the war.[4] Key civilian advisors to President Roosevelt included Secretary of War Henry L. Stimson, who mobilized the nation's industries and induction centers to supply the Army, commanded by General George Marshall and the Army Air Forces under General Hap Arnold. The Navy, led by Secretary of the Navy Frank Knox and Admiral Ernest King, proved more autonomous. Overall priorities were set by Roosevelt and the Joint Chiefs of Staff, chaired by William Leahy. Highest priority went to the defeat of Germany in Europe, but first the war against Japan in the Pacific was more urgent after the sinking of the main battleship fleet at Pearl Harbor.