The United States of America had been in control of the Philippines for many years. In 1900, they had thousands of troops stationed on the Philippine islands. This marked the US out as one of the prominent powers in the Far East, rising in the wake of the power vacuum caused by the decline of China. Another one of these rising powers, carving out an empire of their own, was Japan. (PROSE: Warring States)
On 9 December 1941, almost 48 hours after their initial attack on Pearl Harbor which had brought the United States into the Second World War, the Japanese attacked the US forces stationed on the Philippine Islands. Unlike at Pearl Harbor, the Americans in the Philippines believed they were sufficiently trained and ready to face to approaching Japanese forces.
However, Lieutenant Terrence Moody was shot down and killed in his P-40 Warhawk above Luzon Island shortly after leaving Clark Air Base without ever seeing the Japanese pilot that dispatched him. (PROSE: Happily Ever After Is a High-Risk Strategy)
After the battle, the Japanese went on to gain control of many more islands throughout the Pacific Ocean which had to be clawed back by the Americans in further years of hard fighting. (PROSE: Endgame)
In 5000, the Philippines took part in World War VI, which ended when the Filipino Army marched on Reykjavik and liberated it from the Supreme Alliance. The Doctor marched alongside them and witnessed the final battle. (TV: The Talons of Weng-Chiang)