Although plans to build a fort were underway from the 18th century, nothing came of it until the establishment of a military outpost on the island in 1857. It was formerly called “Principe de Asturias” but renamed “Principe Alfonso” in 1878. The fort is described as polygonal with a tower in the middle and facing the sea. The construction of the fort by the military began after the outpost was established.
The southern tip of Palawan (Paragua) and the outlying islands, did not figure much in the strategies of Spain until the 19th century when the British had established a trading post in the nearby island of Balambagan. Through this trading post the British controlled commerce in the “Sulu Zone.” The military began fortifying Palawan by establishing military and naval detachments throughout the island and its adjacent islands and islets.