Yazid's death and the subsequent withdrawal of the Umayyad army from the Hejaz afforded Ibn al-Zubayr the opportunity to realize his aspirations for the caliphate. He immediately declared himself "amīr al-muʾminīn" (commander of the faithful), a title traditionally reserved for the caliph, and called for the Muslims to give him their oaths of allegiance. With the other potential Hejazi candidates dead, Ibn al-Zubayr remained the last contender for the caliphate among the anti-Umayyad factions in Mecca and Medina and these groups recognized him as their leader. An exception to this came from the Banu Hashim clan to which Muhammad and the Alids belonged and whose support Ibn al-Zubayr deemed important for his own legitimacy as caliph. The leading representatives of the clan in the Hejaz, Muhammad ibn al-Hanafiyya, the half-brother of Husayn ibn Ali, and their cousin Abd Allah ibn Abbas, withheld their oaths citing the need for a stronger consensus in the wider Muslim community. Irritated, Ibn al-Zubayr besieged the clan's neighborhood in Mecca and imprisoned Ibn al-Hanafiyya to pressure the Banu Hashim. Meanwhile, the Kharijites under Najda ibn Amir al-Hanafi in the Yamama (central Arabia) abandoned Ibn al-Zubayr once he forwarded his claim to the caliphate, an institution they rejected, and refused to embrace their doctrine.