Much of Eastern Arabia was controlled by the Usfurids in 1253, but control of the region was later seized by the prince of Ormus in 1320. Qatar's pearls provided the kingdom with one of its main sources of income. The Portuguese defeated the Ormus by 1507 following the destruction of their fleet by Afonso de Albuquerque's forces. However, Albuquerque's captains grew rebellious and he was compelled to abandon the Ormus island. Ultimately, in 1515, King Manuel I killed Sultan Saifuddin's vizier Reis Hamed, pressuring the sultan to become a vassal of King Manuel.