In 815 Isa was dispatched, together with Warqa' ibn Jamil, Hamdawayh ibn Ali, and Harun ibn al-Musayyab, to recapture Mecca, Medina and the Yemen, which had fallen to Alid rebels. Warqa' and Isa's forces advanced against Mecca and, after linking up with the deposed governor of the Yemen, defeated the anti-caliph Muhammad ibn Ja'far al-Sadiq and entered the city in early 816. A few months later Isa defeated a force sent to Mecca by Ibrahim ibn Musa al-Jazzar, who had seized control of the Yemen, and around the same time Muhammad ibn Ja'far agreed to surrender and abdicate.