Jolo (hōˈlō, hōlōˈ) [key], island (345 sq mi/894 sq km), Sulu Archipelago, the Philippines. The seaport city, Jolo (1990 pop. 53,055), on the northwest coast of the island, is the capital of Sulu prov., the trading and shipping hub of the archipelago, and a Muslim center. An ancient walled city, it was once a pirate base and served as the residence of a sultan until the sultanate was abolished in 1940. The city was almost completely destroyed in 1974 when fighting erupted between government forces and Moro (Muslim) insurgents who were seeking to establish a secessionist state. After the battle, the rebels withdrew into the island's interior to fight a war of attrition that lasted until a detente was reached in 1990. Fundamentalist Islamic rebels on the island were involved in hostage-taking incidents in 2000, provoking a military assault in response, and Jolo has been the scene of fighting with Moro rebels several times since.