Al-Mansur an-Nasir (died 1462) was an imam of the Zaidi state in Yemen who held power in parts of the northern Yemeni highland in 1436-1462. The old imam al-Mansur Ali bin Salah ad-Din died from the plague in 1436. His position was then claimed by three different Sayyids, of which one was al-Mansur an-Nasir. He was the great-great-grandson of the imam al-Mutawakkil al-Mutahhar bin Yahya (d. 1298). The two other competitors were al-Mutawakkil al-Mutahhar (d. 1474) and al-Mahdi Salah ad-Din (d. 1445). Al-Mansur an-Nasir tried to strengthen his claim by marrying the granddaughter of al-Mansur Ali. At this time, the once powerful Rasulid Dynasty in lowland Yemen was quickly crumbling, and fell altogether in 1454. The new Sunni lowland regime was the Tahiride Dynasty, which was engaged in warfa