 When this regent died in July 1149, Mujir ad-Din took his place as the rightful heir of Damascus.He was a weak ruler, however, and Damascus came under the influence of Nur ad-Din Zangi, emir of Aleppo and Mosul, who had imposed his dominance over the city in the aftermath of the Second Crusade.In 1150 Nur ad-Din recognized Mujir ad-Din as ruler of Damascus, but in 1151 Mujir ad-Din allied with the crusaders against Bosra, angering Nur ad-Din.