The United States Air Force came from a long line of service before it was finally established on September 18, 1947. This branch of United States Military began as the Aeronautical Division of the US Signal Corps on August 1st, 1907. On July 18th, 1914 the Aeronautical Division became the Aviation Section. Four years later on May 20th, 1918 the Division of Military Aeronautics was established and existed for four days until May 24th, 1918 when it became the Air Service which it remained until July 2nd, 1926. In 1926 the Air Corps took over the role of the Air Service until the United States Air Force was established in 1947. In June of 1941 the Army Air Forces assumed the role of the Air Corps which remained as a combat arm of the Army Air Force through 1947.