THE CALIPHATES OF EL-MANSŪR, EL-HĀDI, AND HĀRŪN ER-RASHĪD
El-Mansur’s troubles did not end with the defeat of `Abdullah and the murder of Abū Muslim. The rebellious Mesopotamians, under their leader Mulabbab esh-Shaybāni, more than once repulsed the troops sent against them by the Caliph, and not till A.H. 138 (755) was order restored by Khāzim ibn Khuzayma.[185] In the meantime a “Magian,” or Zoroastrian of Nīshāpūr, named Sinbad,[186] disgusted at the murder of his patron Abū Muslim, rose in rebellion to avenge the blood of the fallen general.[187] He soon found himself at the head of a large following,[188] and gained possession of Nīshāpūr, Kūmis, and Ray. In the town last mentioned the treasure which had been left there by Abū Muslim fell into his hands. Against him El-Mansūr despatched Jahwar[189] ibn Marrār el-`Ijlī, at the head of 10,000 men, who encountered and put to flight the rebels between Hamadān and Ray. Sinbad escaped from the field of battle, but was overtaken and killed between Tabaristān and Ray, his revolt having lasted just seventy days.[190]
In A.H. 138 (755) Jahwar was deprived of his command for having failed to deliver over to the Caliph the treasure of Abū Muslim which had fallen into his hands. He now in turn took up arms against the Caliph, who sent a force against him under Mohammad ibn el-Ash`ath. Jahwar suffered a crushing defeat and fled to Āzerbāyjān, whither he was pursued and slain.
Although El-Mansūr had now, A.H. 139 (756), secured comparative tranquillity and recognition of his sovereign rights in most of his dominions, the distant province of Khorāsān, yearly rising in importance, was still under the heel of the rival faction of the Hāshimites and the Shi`ites, quite apart from minor sectarian movements which rendered the attempt to maintain order there almost hopeless.
In the year A.H. 140 (757) the Shi`ites broke out into open revolt, in the midst of which the then governor, Abū Dā´ūd Khalid ibn Ibrāhim, died.[191] His successor, `Abd el-Jabbār, was powerless to assert his authority, and, on learning that he was about to be dismissed from his office, turned against El-Mansūr. Khāzim ibn Khuzayma, who had already distinguished himself in Mesopotamia, accompanied by the Caliph’s son and successor El-Mahdi, at once marched against `Abd el-Jabbār and his following, A.H. 141 (758). `Abd el-Jabbār was, however, captured by his own people and sent, mounted backwards on an ass, to the Caliph, who, after extorting from him by torture all his treasure, put him to death. The governorship of Khorāsān was now given to El-Mahdi,[192] the Caliph’s own son and successor--an appointment which seems to indicate the growing importance of the far Eastern provinces.