Army Ground Forces traced their origins back to General Headquarters, United States Army (GHQ), which were activated on 26 July 1940. Although inactive before this date, GHQ had long featured in mobilization plans as far back as 1921 as a headquarters for directing US field armies overseas, similar to that of the American Expeditionary Forces in World War I. This was not realized in practice because the war was fought in many theaters, so overall direction was exercised by the War Department's General Staff. GHQ also did not become the equivalent of a theater command for the Zone of Interior; administrative authority was exercised by the G-4 of the War Department's General Staff through the Corps Areas and Service Commands. Instead, GHQ was drawn into the enormous task of raising and training an army.