Spanish–Moro conflict
The Spanish initiated the conflict by conquering the Philippines and invading Moro territory in an effort to subjugate the region to their rule since the 1500s. When the Spanish conquered the Muslim Kingdom of Maynila, a vassal of the Sultanate of Brunei, the Islamic rajah, Rajah Sulayman resisted the Spanish. Manila then became the capital of the Spanish Philippines after the conquest, with the Spanish forcibly converting people to Catholicism. The Spanish–Moro Wars started with the Castille War, a war between Spaniards and the Sultanate of Brunei. (The term "Moro" at this time included Muslim Tagalogs who were ruled by the Sultanate of Brunei).
Military history of the Philippines during World War II
The Commonwealth of the Philippines was attacked by the Empire of Japan on December 8, 1941 nine hours after the attack on Pearl Harbor (the Philippines is on the Asian side of the international date line). The United States of America controlled the Philippines at the time and possessed important military bases there. The combined American-Filipino army was defeated in the Battle of Bataan and the Battle of Corregidor in April 1942, but guerrilla resistance against the Japanese continued throughout the war. Uncaptured Filipino army units, a communist insurgency and supporting American agents all played a role in the resistance. Due to the huge number of islands, the Japanese never occupied many of the smaller and more minor islands. Japanese control over the countryside and smaller towns was often tenuous at best.