Jolo () is a volcanic island in the southwest Philippines and the primary island of the province of Sulu, on which the capital of the same name is situated. It is located in the Sulu Archipelago, between Borneo and Mindanao, and has a population of approximately 500,000 people. The island is the location of the Jolo Group of Volcanoes, and contains numerous volcanic cones and craters, including the active Bud Dajo cinder cone. It has been the headquarters of militants from the terrorist group Abu Sayyaf. History After a series of less-than-successful attempts during the centuries of Spanish rule in the Philippines, Spanish forces captured the city of Jolo, the seat of the Sultan of Sulu, in 1876. On that year, the Spanish launched a massive campaign to occupy Jolo. Spurred by the need to curb slave raiding once and for all and worried about the presence of other Western powers in the south (the British had established trading centers in Jolo by the 19th century and the French were offering to purchase Basilan Island from the cash strapped government in Madrid, Spain), the Spanish made a final bid to consolidate their rule in this southern frontier. On 21 February of that year, the Spaniards assembled the largest contingent against Jolo, consisting of 9,000 soldiers, in 11 transports, 11 gunboats, and 11 steamboats. Headed by Admiral Jose Malcampo, the contingent captured Jolo and established a Spanish settlement with Capt. Pascual Cervera appointed to set up a garrison and serve as military governor; he served from March 1876 to December 1876 followed by Brig. Gen. Jose Paulin (December 1876 – April 1877), Col. Carlos Martinez (Sept 1877 – Feb 1880), Col. Rafael de Rivera (1880–1881), Col. Isidro G. Soto (1881–1882), Col. Eduardo Bremon, (1882), Col. Julian Parrado (1882–1884), Col. Francisco Castilla (1884–1886), Col. Juan Arolas (1886–1893), Col. Caesar Mattos (1893), Gen. Venancio Hernandez (1893–1896) and Col. Luis Huerta (1896–1899). By 1878 the Spaniards had fortified Jolo with a perimeter wall and tower gates, built inner forts called Puerta Blockaus, Puerta España, and Puerta Alfonso XII; and two outer fortifications named Princesa de Asturias and Torre de la Reina. Troops, including a cavalry with its own lieutenant commander, were garrisoned within the protective confine of the walls. From Jolo, in 1880 Col. Rafael Gonzales de Rivera who was appointed the governor dispatched the 6th Regiment to Siasi and Bongao islands. The Spaniards