The Philippines campaign, Battle of the Philippines or the Liberation of the Philippines (), codenamed Operation Musketeer I, II, and III (), was the American, Mexican, Australian and Filipino campaign to defeat and expel the Imperial Japanese forces occupying the Philippines during World War II. The Japanese Army overran all of the Philippines during the first half of 1942. The liberation of the Philippines commenced with amphibious landings on the eastern Philippine island of Leyte on October 20, 1944. United States and Philippine Commonwealth military forces were progressing in liberating territory and islands when the Japanese forces in the Philippines were ordered to surrender by Tokyo on August 15, 1945, after the dropping of the atomic bombs on mainland Japan and the Soviet invasion of Manchuria.