 Prior to gaining separate representation, areas now under the jurisdiction of Basilan were represented under the Department of Mindanao and Sulu (1917–1935), Zamboanga Province (1935–1953), Zamboanga del Sur (1953–1972) and Region IX (1978–1984).Even after separating from Zamboanga City and receiving its own charter on June 16, 1948, the city of Basilan remained part of the representations of the Province of Zamboanga (pursuant to Section 42 of Republic Act No.288) and of the Province of Zamboanga del Sur (pursuant to Section 7 of Republic Act No.