The Spaniards were never secured in Jolo, and by 1878 they had fortified the town 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 when Sultanate of Sulu formally recognised Spanish sovereignty on Sulu and Tawi-tawi in middle of 19th century, but these areas remained partially ruled by the Spanish as their sovereignty was limited to military stations and garrisons and pockets of civilian settlements. Troops, including a cavalry unit with its own lieutenant commander, were garrisoned within the protective walls. In 1880 Colonel Rafael Gonzales de Rivera, who was appointed by the Governor General, dispatched the 6th Regiment to Siasi and Bongao Islands.
The Spaniards were never secured in Jolo, and by 1878 they had fortified the town 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 when Sultanate of Sulu formally recognised Spanish sovereignty on Sulu and Tawi-tawi in middle of 19th century, but these areas remained partially ruled by the Spanish as their sovereignty was limited to military stations and garrisons and pockets of civilian settlements. Troops, including a cavalry unit with its own lieutenant commander, were garrisoned within the protective walls. In 1880 Colonel Rafael Gonzales de Rivera, who was appointed by the Governor General dispatched the 6th Regiment to Siasi and Bongao Islands.