The expansion of Islam
During the reign of Sultan Bolkiah in 1485 to 1521, the Bruneian Empire decided to break the Dynasty of Tondo's monopoly in the China trade by attacking Tondo and establishing the State of Selurong (now Manila) as a Bruneian satellite-state. A new dynasty under the Islamized Rajah Salalila was also established to challenge the House of Lakandula in Tondo. Islam was further strengthened by the arrival to the Philippines of traders and proselytizers from Malaysia and Indonesia. The multiple states competing over the limited territory and people of the islands simplified Spanish colonization by allowing its conquistadors to effectively employ a strategy of divide and conquer for rapid conquest.