would occupy it until January 1945. During the Japanese invasion, another type of local government was set up on January 22, 1942. During the Japanese occupation, Clark Air Base then became a major center for staging Japanese air operations. Japanese aircraft flying out of Clark participated in the Battle of Leyte Gulf, considered to be the largest naval battle of the Second World War and possibly the largest naval battle in history. Clark Air Base was recaptured by the Americans in January 1945, after three months of fierce fighting in the Philippines. After three years of atrocities committed by Japanese forces, the town and the rest of the Philippines were finally liberated by the combined United States and Philippine Commonwealth troops in 1945. The building of the general headquarters of the Philippine Commonwealth Army and Philippine Constabulary was situated in Angeles from January 1945 to June 1946, during and after World War II. Independence and cityhood After World War II, the Philippines gained independence from the United States on July 4, 1946, but then would be tied to a neo-colonial relationship. The "Treaty of General Relations" signed on independence day itself signified the Americans' withdrawal and surrender of possession, control and sovereignty over the Philippines, except the use of their bases. It was followed by the Philippine-American Military Bases Agreement on March 14, 1947, allowing the U.S. to maintain territorial integrity and sovereignty over Clark Air Base and Subic Naval Base for the next 44 years. Clark occupied 63,103 hectares and served as the tactical operational U.S. air force installation in the entire Southeast Asian region that had the capacity to accommodate the U.S. military transport planes, which served the entire Western Pacific. Through the years, although Fort Stotsenburg continued to expand to become what is now known as Clark Air Base, Angeles, despite its proximity to the American camp, did not progress fast and remained fairly small until the end of World War II. It was finally inaugurated on January 1, 1964, as a chartered city under Republic Act No. 3700 and then it entered a period of tremendous growth that has resulted in its present position as the "Premier City in Central Luzon." It was then Mayor Rafael del Rosario's brainchild that Angeles became a city. He gained the distinction of being the last municipal mayor of Angeles. He was assisted in the preparation of the City Chapter