Oman is situated on the Arabian peninsula and has been, since antiquity, a trade center in the Persian Gulf and Indian Ocean. The Portuguese took Oman's principal port, Muscat in 1508 and held it for over 150 years. At that point, the Ottomans arrived for an 82-year long stay. The sultanate of Oman was consolidated under Ahmed ibn Said of Yemen in 1744. The present royal family are his descendants. Oman controlled African Zanzibar, southern coastal Iran, and the area between Pakistan and Iran, in the early 1800s. Nearly all these possessions were lost over the course of the 19th century except for an area ceded to Pakistan in 1958 (there was a monetary settlement). Oman became a British protectorate in 1891. The protectorate came to an end in 1971. Oman's wealth is derived from oil, as the country lacks other natural resources.