Fars at the time was one of several provinces that had been assigned to the Tahirid family, who held the important governorships of Khurasan and Baghdad.
Soon, however, the army became disgruntled with 'Abdallah, who refused to pay their salaries; as a result, 'Ali was able to convince the troops to support him in a new uprising.
[2] Al-Tabari's chronicle notes that, in the year 864, the army of Fars revolted against 'Abdallah ibn Ishaq, looted his residence and forced him to flee; however it does not explicitly name 'Ali as being involved with this event.
[3] It does not mention 'Ali until the events of 868 and 869, at which point he was serving as the caliphal governor of Fars; it also describes 'Ali as having previously been in the service of the Tahirids.
According to the biographer Ibn Khallikan, the resulting battle took place on April 21, 869; during the course of the fighting, Ya'qub's army broke through the enemy's front line, and soon 'Ali's men were abandoning the field in a panic and retreating back into Shiraz.
Ibn Khallikan, however, states that he was tortured on the orders of Ya'qub to the point that he went insane, and was ultimately imprisoned in a fortress in Kerman.