Abdallah ibn Mu'awiya
Descent and rise to the imamate
Abdallah ibn Mu'awiya was a great-grandson of Ali's brother, Ja'far ibn Abi Talib. Following the death of Ali's grandson Abu Hashim in 703, the leadership of the Alid cause was vacant, and several candidates vied for it: one party claimed that Abu Hashim had transferred his rights to the Abbasid Muhammad ibn Ali, while another faction wanted to proclaim Abdallah ibn Amr al-Kindi as the next imam. The latter, however, proved unsatisfactory, and Abdallah ibn Mu'awiya was chosen instead.
Abdallah claimed not only the imamate, but maintained that, according to K.V. Zetterstéen, "both the godhead and the prophetic office were united in him, because the spirit of God had been transferred from the one Imam to the other and had finally come to him". Consequently, his followers embraced the concept of reincarnation and rejected the resurrection of the dead.
Rebellion and death
In October 744, Abdallah and his followers rebelled in Kufa, and joined by other Alid sympathizers (especially Zaydis), took control of the city and expelled its governor. The reaction of the governor of Iraq, Abdallah ibn 'Umar ibn Abd al-Aziz, however, was swift, and he marched on Kufa. Most of the citizens deserted the Alid cause, but the Zaydi contingent fought with enough determination to allow Abdallah to withdraw from Kufa, first to al-Mada'in and thence to Jibal.
Despite his defeat at Kufa, volunteers opposed to the Umayayd regime continued to flock to his banner, including remnants of the Kharijites defeated by Marwan II and some Abbasid followers. Taking advantage of the turmoils of the Third Fitna and the burgeoning Abbasid Revolution in Khurasan, which debilitated the UMayyad government, he managed to extend his control over large parts of Persia, including most of Jibal, Ahwaz, Fars and Kerman. He established his residence first at Isfahan and then at Istakhr.
Finally, Marwan II dispatched an army under Amir ibn Dubara against Abdallah. The Alid's forces were utterly defeated at Marw al-Shadhan in 746/7, and his rule over Persia collapsed. Abdallah himself managed to flee to Khurasan, where the Abbasid leader Abu Muslim executed him.
Some of his followers refused to believe his death, and believed that he would return as the mahdi, forming the sect known as the "Janahiyya". Others, the so-called "Harithites", believed that he was reincarnated in the person of Ishaq ibn Zayd ibn al-Harith al-Ansari.