In May 1182, Saladin captured Aleppo after a brief siege; the new governor of the city, Imad al-Din Zangi II, had been unpopular with his subjects and surrendered Aleppo after Saladin agreed to restore Zangi II's previous control over Sinjar, Raqqa, and Nusaybin, which would thereafter serve as vassal territories of the Ayyubids. Aleppo formally entered Ayyubid hands on 12 June. The day after, Saladin marched to Harim, near the Crusader-held Antioch and captured the city. The surrender of Aleppo and Saladin's allegiance with Zangi II had left Izz al-Din al-Mas'ud of Mosul the only major Muslim rival of the Ayyubids. Mosul had been subjected to a short siege in the autumn of 1182, but after mediation by the Abbasid caliph an-Nasir, Saladin withdrew his forces.