After rounding the Cape of Good Hope, the Portuguese occupied the port of Muscat in Oman for 143 years (1507-1650). About 100 years after they were driven out by locals, the current ruling dynasty cemented power in 1744. Holding a strong strategic position at the mouth of the Persian Gulf, the Omani Empire competed with Portugal and Britain for influence in the Indian Ocean from the late C17th. Oman's colonial focus was the Swahili Coast. The Omanis ejected the Portuguese from Zanzibar and the other areas north of Mozambique. Zanzibar became the main slave market. Slavery was outlawed in Oman in 1970 after Sultan Qaboos ousted his father in a palace coup. Oman remains an absolute monarchy, but gradual reforms have been introduced. Unlike most of its neighbours, it only has modest oil reserves and so doesn't have an oil-dependent economy.