The Umayyads fell in 750 to rebel troops from eastern Iran, more precisely Khurāsān. The troops had been recruited by Iraqi dissidents who named themselves and their Khurāsānī followers Hāshimiyya, adherents of Hashim's descendants, and who called for allegiance to the riḍā of the Prophet's family. The sources claim that the term al-riḍā was a mere cover for an ‘Abbāsid, but it seems more likely that it stood for a Hāshimite to be elected by shūrā. (For the Hāshimite clan, the reader may consult chart 3; for its ‘Abbāsid branch, chart 5.) The main candidate of the Hāshimiyya seems to have been the ‘Abbāsid known as Ibrāhīm al-imām, whose election they may indeed have regarded as a foregone conclusion: to that extent, the sources may be right when they claim that al-riḍā was a mere cover name. Ibrāhīm died in the jail of the last Umayyad caliph, and attempts to get a shūrā of Hāshimites together after the conquest of Iraq came to nothing when the ‘Alīds refused to participate. It was impatient generals who elected Abū ‘l-‘Abbās (750–4), the first ‘Abbāsid caliph. The revolution had raised strong messianic expectations of the apocalyptic type in Khurāsān. Like al-Mukhtār, the Hāshimiyya saw the Mahdi as an avenger, and they too associated him with a vizier who organized the movement on his behalf. The first caliph, Abū ‘l-‘Abbās, duly styled himself al-mahdī to indicate that the world had now been filled with justice.