Mauritania was first inhabited by black peoples and Berbers. From the 7th Century, following the advent of the Arabs in Northern Africa, the Berbers in the region were converted to the Islamic faith and they in turn proselytized the Tukulor and other black communities in the Sahel region. As was the case in Morocco, Arab and Berber intermixing led to the emergence of Moors (derived from the Latin Mauri or French Maures) who viewed themselves as al-Bidan (white) as opposed to their al-Sudan (black) neighbors. Portuguese slave traders established a base on Arguin Island (Tidra) from 1443. The French took over the region in the 1930s. In 1960, over strenuous opposition from Morocco, which laid claim to the territory, Mauritania became independent under President Moktar Ould Daddah (son-in-law of French president Charles de Gaulle). Ould Daddah's party had won all the seats in a 1959 general election. In 1976 Spain ceded Spanish (Western) Sahara on a 50/50 basis to Morocco and Mauritania. The Polisario guerrillas, who sought independence for Western Sahara, attacked targets in Mauritania, drawing it into a protracted and costly war. In 1997, in the midst of growing opposition to this unpopular war, Ould Daddah was ousted by Lt-Col. Khouna Ould Haidalla, who assumed the presidency and appointed Col. Maaouiya Ould Sid'Ahmed Taya as his prime minister. Mauritania dropped its territorial claims, leaving the way clear for Morocco to expand its influence over all of Western Sahara. In 1984 Taya assumed the presidency. He exercised autocratic rule until 1992 when his Parti Républicain Démocratique et Social (PRDS), or Social and Democratic Party, won in free elections. Tension between the Moorish and black non-Moorish groups has eased since the restrictions on political parties were lifted after the adoption of a new democratic constitution at a referendum in 1991. Pres. Taya was reelected in 1997 and again in November 2003.