 In 697/98, Khurasan was incorporated into al-Hajjaj's governorship and he appointed al-Muhallab as his deputy governor over the province.The Kharijite rebellions had not taken root in Khurasan and at the time of his appointment, the Tamim formed the strongest army faction in the province.According to historian Muhammad Abdulhayy Shaban, al-Hajjaj viewed the unruly Tamim's dominance as the major impediment to his policies of centralization and expansion in the eastern half of the Caliphate.