 Basilan Island's reputation as a staging-ground

Spanish and Tausug fleets engaged each other in sea battles and skirmishes not far from the western shores of the islands.Many of their ships were scuttled or sunk, sometimes with precious cargoes of traded goods and Mexican silver pieces meant for the fort in Zamboanga and the naval squadron at Isabela, as well as goods en route to Jolo from the Mindanao mainland.The Spanish Pigafetta expedition landed on a group of islets west of the main island of Basilan, where they found precious pearls; subsequent Spanish cartographers aptly named these the "Isletas de Perlas" (Pearl Islets).