Ahmad al-Mansur (ä´məd äl-mänsōōr´, Arabic äkhmäd´) [al-Mansur,=the victorious], d. 1603, emir of Morocco (1578–1603). Proclaimed ruler after his brother's death at the battle of Ksar el Kebir, he gained prestige from the victory over Portugal. In addition, the ransom of the Portuguese captives made him wealthy. He was able to give Morocco a quarter-century of relative peace and prosperity. His conquest of Timbuktu (1590–91) marked the peak of Morocco's extension into the territory S of the Sahara. The cost of maintaining an army at so great a distance prevented him from gaining any permanent benefit from the conquest. He engaged in a commercial correspondence with Queen Elizabeth I of England and encouraged foreign trade.