Yazid ibn al-Muhallab
Shortly after the death of Umar in February 720, Adi received a message from the new caliph Yazid II informing him that Yazid ibn al-Muhallab had escaped from prison and that he was likely heading toward Iraq. On the caliph's orders, Adi arrested and imprisoned the Muhallabids who were in Basra and prepared for an confrontation with Yazid; the local army was organized and a trench was dug around the city.