jan 1, 1945 - The Philippines became a territory of the United States after the Spanish-American War. Under the December 10, 1898 Treaty of Paris, Spain ceded the islands to the United States for $20 million. In 1935 the Philippines became a self-governing commonwealth. Japan took over the country from 1942-1944, but the United States regained the islands in 1945, and full independence was granted in July, 1946.