By the 16th century, four Moro states were established, asserting their independence from the Philippines, which was acknowledged during the Spanish-American War. The Bates Treaty, signed in 1899, recognized the Sulu Sultanate's sovereignty, but its abrogation in 1904 led to the Moro-U.S. War until 1913, and a series of peace agreements followed, including the 1976 Tripoli Agreement. Ongoing disputes over territorial and resource management issues persist between the Moro National Liberation Front and the Philippine government, complicating the implementation of various agreements aimed at achieving autonomy for Bangsamoro regions.