The Alids were totally disappointed while seeing the Abbasids taking power in the name of Ahl-al-Bait. The first task before Abbas as-Saffah therefore was to break the alliance with the Alids who were yet strong and could be dangerous. During his short rule of less than four years, he was kept fully occupied in meeting numerous insurrections and in ruthlessly killing those Alids who were suspected. The first to pay his life was Abu Salama. Abul Abbas died in 136/754, during which period, the Alids in Medina, disorganized by the frustration of their hopes, kept quiet. But when Abu Jafar Mansur, the brother of Abul Abbas as-Saffah assumed the caliphate, the Alids embittered by the usurpation of their rights by the house of Abbas, began to voice their complaints. An-Nafs az-Zakiyya, the son of Abdullah al- Mahd openly refused to take oath of allegiance to Mansur. The traditionalists circle of Medina supported him and upheld his cause. According to Tabari (3rd. vol., p. 200), "Malik bin Anas declared that the oath sworn to the Abbasids was no longer binding as it had been taken under compulsion."
Soon afterwards in 137/755, Abu Muslim was lured to Iraq and murdered. In 141/758, Mansur massacred a group of the Rawandiyya who besieged his palace. Caliph Mansur thus had to face the most threatening opposition from the Alids to the newly established authority of his house. He firstly concentrated his efforts on two basic points. The first was to justify the rights of his house on religious ground. The second was to gain for his caliphate the acceptance of the Muslims. The sources agree to mention that caliph Mansur also persecuted Imam Jafar Sadik many times, but the latter retained his equanimity.
The Abbasids had also adopted a very cruel policy towards the Umayyads, and many members of the family were ruthlessly executed. Some Umayyads, however, escaped and sought refuge among the nomadic tribes, one of them being Abdur Rehman (138-173/756- 788), the grandson of Hisham. He escaped to Rah, near Euphrates, where he began to prepare for the long journey to Africa, where few other Umayyad princes had already taken refuge. On 1st Shawal, 138/March 8, 756, he entered Archidona, the capital of Regio, where he was declared an amir. Hence, he became the king of the Umayyads in the southern districts of Spain.
Returning to the thread of our main narratives, it is recounted that Jafar Sadik died in 148/765 in Medina after the Imamate of 34 years and 7 months. Upon his death the Imamate devolved upon his elder son, Ismail.