Spanish presence in this area near Malabang begins in the 17th century. The site of La Sabanilla is described by José Nieto de Aguilar (1894) as a short distance from Malabang. Of Malabang he notes “This is a most important (take off) point for whatever (military) operation is planned for the lake (of Lanao). It connects with the lake directly through a road which is about 50 kilometers in length, and ends in the settlement (ranchería) of Ganasi. A short distance from the present palisade, exists some ruins of the fort La Sabanilla, constructed in 1639, a site which could serve well for constructing a strong permanent fort utilizing the foundations and the materials accumulated by our predecessors.” Other sources give the year as 1649 and attribute the construction of the fort to the Jesuit Melchor de Vera who earlier had built Fort San José at Zamboanga, the predecessor of Fort Pilar.
La Sabanilla figured in the history of the pacification of Mindanao during two eras:
— the 17th century when Sultan Kudarat, wanting to secure Cotabato against the incursions of the Spanish launched a war to expand his territory and drive out the Spaniards from the island. Kudarat’s forces reached as far as northern Mindanao, using the narrow land passage between Illana Bay to the south and Panguil Bay to the north. To contain the advance of Kudarat, the Spanish established a fort in La Sabanilla. This 17th century structure may started as a palisade but may have been reconstructed at a later date with stone and mortar in response to the governor general’s decree of 2 March 1649.It was abandoned in 1662 when troops south were ordered to consolidate in Manila to prepare for an impending Chinese attack. La Sabanilla was planned as a series of fortifications beginning north in the area of Sibuguey.
— The second time it figures in Mindanao history happens in the 19th century when it is proposed that La Sabanilla be rebuilt. La Sabanilla was located near Malabang, the site of a fort constructed in the 1880s as part of a campaign to expand, strengthen and consolidate Spanish rule in Mindanao. In the 19th century, a military detachment assigned to La Sabanilla was protected by a fortified outpost, built on wooden piles in the shallows of Illana Bay. Late-19th century engravings depict the outpost as a simple boxy structure probably made of timber and thick lumber.