Territorial disputes in the southern Philippines have existed since the 14th Century, when Muslim forces pushing north from the southern tip of the Sulu Islands established their power as far north as Zamboanga Peninsula on Mindanao.
Two centuries later Spain defeated these Moros (Moors) and held the Philippines until it was seized by the United States in 1898 in the Spanish-American War.
But Islam retained a strong toehold, and a claim, on Mindanao.
Muslim aspirations on Mindanao remain embodied in the separatist movement of the Moro National Liberation Front (MNLF).
Muslim organizations contend that a quarter of the Philippines’ 65 million people follow Islam. A 1990 government census concluded that there were only 10 million Muslims. Christians, mainly Catholics, fear the real Islamic goal is secession and an Islamic state on Mindanao.