Isa ibn Musa

He would retain the post for fifteen years—according to Hugh N. Kennedy, the second longest tenure in the Abbasid period after that of Dawud ibn Yazid al-Muhallabi at Sind in the early 9th century.

This move was necessary to prevent Abu Muslim, the powerful and popular commander who had initiated the Abbasid Revolution in Khurasan and had ruled the province since, from rising to the position of king-maker.

[6] It was Abdallah ibn Ali in Syria who rose in revolt instead, commandeering an army he had originally raised to campaign against the Byzantine Empire and marching with it into Iraq.

[9] Isa had cordial relations with Abu Muslim, and was left unaware of al-Mansur's plot to kill the dangerously powerful ruler of Khurasan until after the deed was done.

[11][12] Muhammad's brother Ibrahim, who had chosen Basra as his base, was more successful, capturing Wasit, Fars, and Ahwaz, but failed to synchronise his revolt with the uprising of Medina.

The reasons for this are not entirely clear, but Kennedy suggests that Isa may have been associated with the aristocratic gentry, the dehqan class, the overthrow of whose power had been one of the aims of the Abbasid Revolution.

[18] Isa nevertheless remained a threat to al-Mansur's rule: his dismissal is given as one of the reasons of the revolt of Ustadh Sis in Khurasan in 768,[23] and as late as 770 some Khurasanis were arrested and brought to Baghdad for championing his cause.

[24] In retirement, Isa built the al-Ukhaidir Fortress, a sprawling fortified palace that, in the words of Kennedy, "demonstrates to this day the power and wealth of the family".

In November he was obliged to witness the proclamation and oath-taking for al-Mahdi's son, Musa (the future al-Hadi, r. 785–786), as heir, and renounce his rights in public and in writing.

[25] He was compensated by another vast sum of money, some ten million silver dirhams, as well as estates in Upper Mesopotamia, but he was, as Kennedy writes, "a broken man".