The caliph on learning that the revolt was due to Ali's tyranny, sent Harthama b.
On the very day of his arrival, Harthama b.
He was here reinforced by troops sent from Khorasan under the command of Harthama b.
He resolved to treat with Harthama, as he was averse to Tahir; but this step caused his ruin.
Tahir succeeded in intercepting him on his way to Harthama, and immediately ordered him to be put to death.
Harthama was ordered to return to Khorasan; Tahir was made governor of Mesopotamia and Syria, with the task of subduing Nasr b.
Sahl hastily sent a messenger to Harthama b.
Harthama, who was deeply offended by his dismissal, refused at first, but at last consented, and at once checked the tide of disaster.
Harthama, having vanquished Abu'l-Saraya, did not go to Hasan b.
Fadl, informed of his intentions, filled the caliph's mind with distrust against the old general, so that when Harthama arrived Mamun had him cast into prison, where he died shortly afterwards.
Mamun had found out also that the general uneasiness was largely due to his treatment of Harthama and Tahir, the latter having been put in a rebellious country without the men and the money to maintain his authority.