In A.H. 120 (737)162 Asad died, and was succeeded by Nasr ibn Sayyar, one of the ablest rulers and generals ever sent to the East in Mohammedan times. He was as generous as he was strong, and seems to have won the affection of those under him. During the nine years of his governorship his position was by no means an easy one, for he had to contend with the growing influence of the `Abbasid faction,163 and to support, with a loyalty worthy of a better cause, the last degenerate representatives of the house of Umayya. His first care on assuming the supreme command was to subjugate the Khakan of the Turks, whose name was Kursul, against whom he led three successive expeditions. The first two seem to have been without result, but in the last, which was directed against Shash, the Khakan fell into his hands and was put to death.164

In the same year Nasr renewed his attempt to subject Shash to the Moslem yoke. The campaign was a bloodless one. He received the submission of Ushrusana, and concluded an advantageous peace with the king of Shash.165 He thereupon appointed a Mohammedan governor of Farghana. In the year A.H. 123 (740) this judicious ruler established order throughout Transoxiana, Khorasan, and Farghana.166 But he had other difficulties to meet which were not of his own making. The star of the Umayyads was in the descendent, and the `Abbasid party were daily adding to the number of their adherents. And, apart from dynastic struggles, the whole of Islam was rent with the dissensions of the rival sects of the Kharijites and the Shi`ites. The sectarian zeal of the latter, which to this day remains the cause of bitter discord in the realm of Islam, began now to make itself felt in Persia and in Central Asia.

In A.H. 125 (742) Hisham, the last Umayyad Caliph of any distinction, died. The dynasty lasted seven years longer, and in that short period no less than four Caliphs167 attempted to restore the fading glory of their house. While such disorders reigned at headquarters there was small hope of quelling sedition in the outlying provinces. The `Abbasid pretender, Ibrahim, thanks to the efforts of his father’s168 emissaries, had now a powerful and rapidly increasing faction in Merv. But Nasr still held command in Khorasan, and his personal influence was still great enough to avert open rebellion. It failed; and the fierce tribal jealousy which always smouldered in Arab breasts burst into civil war. The two rival factions were the Yemenites and the Modharites. Nasr ibn Sayyar belonged to the tribe of Modhar, and bestowed the highest offices on his clansmen. In fact, all the towns of Khorasan were governed by members of one or the other of the three principal branches of the tribe, Asad, Temim, or Kinana. Now, there was a man of the tribe of Azd called, after his birthplace, Juday` El-Kirmani, who, before the promotion of Nasr, had held a higher position, and retained some authority among his own people. To him came the Beni Rabi`a with complaints of the partiality of Nasr. He promised his intercession with the governor. On attempting remonstrance he raised Nasr’s ire, and was cast into prison, whence escaping169 he rejoined his own people. All efforts at reconciliation proving fruitless, the rival parties had recourse to armed strength. In A.H. 127 (744) Harith ibn Surayj, who was permitted to return to Khorasan from his captivity in Farab, set up his standard at Merv, and, gathering many followers around it, openly revolted against Nasr. In the following year Nasr called upon him to swear allegiance to the Caliph Merwan, but Harith refused, and boasted that he was “the man with the black flag”170 who was to overthrow the Umayyad dynasty. Hostilities thereupon commenced between Nasr and Harith, in which the latter was worsted. He fled to the camp of El-Kirmani, whom Nasr had meanwhile been vainly endeavouring to conciliate.

Their combined forces now marched against Nasr, whom they defeated in a pitched battle. Nasr fled to Nishapur, while the allies occupied Merv, where, however, dissensions arose between them which cost Harith his life, A.H. 128 (745).171

It was in the midst of these disorders that Abu Muslim, the virtual founder of the `Abbasid dynasty, raised the black banner in Khorasan. The advent of the `Abbasids to the Caliphate was an event of such moment for the future of Central Asia that it is necessary in this place to give a brief account of the rise of the new dynasty. The fall of the Umayyads was the death-knell of unity in Islam. In spite of numberless rebellions in all parts of their conquered provinces the Umayyads had never recognised independent rulers, but with the establishment of the house of `Abbas there set in a general dismemberment of the empire of the Caliphs. The origin of the dispute between the Hashimites (or `Abbasids) and the Umayyads dates back to a period anterior to the birth of Mohammed. It was a rivalry between the two chief stocks of the house of Koraysh.172 We have seen above that, although Mohammed, on first declaring his mission, met with opposition from his own tribe, after the conquest of Mekka they temporarily reconciled the conflicting interests. So after the Prophet’s death discussions again arose between `Ali and the Caliph Mo`awiya. The Kharijites, who demanded a purely theocratic rule, were also continually in a ferment. After the tragic death of Husayn, the son of `Ali, at Kerbela, a party arose devoted to the house of `Ali, and claiming the succession of his family to the Caliphate, who called themselves the Shi`a (or faction), and who are known to Europeans as the Shi`ites.

In the reign of Hisham (A.H. 105), Mohammed, the great-grandson of the Prophet’s uncle, `Abbas, who was living in retreat in the south of Palestine, began to advance his claims to the Caliphate. Emissaries and secret deputations were sent to all the principal towns of Persia, `Irak, and Khorasan, and, in spite of the severe measures taken to check the movement, the cause of the Hashimites began rapidly to spread. The Shi`ites and the Kharijites were induced to make common cause with the Hashimites, on the plea that the only object of the movement was to secure the Caliphate for a member of the Prophet’s own family.

In the year A.H. 125 (742) Mohammed visited Mekka, and in the same year Abu Muslim was taken there on a pilgrimage by a party of the Hashimite faction. This Abu Muslim, whose real name was `Abd er-Rahman ibn Muslim, was a native of Khorasan, and had been a saddler in the service of a distinguished Arabian family.173 While residing at Mekka he attracted the attention of the `Abbasid claimant, who at once singled him out as a youth of great promise,174 and prophesied that Abu Muslim would be greatly instrumental in bringing the `Abbasids to power. He spent the two following years in journeys between Khorasan and Homayma, in order to promote the cause and report its progress. By means of an active propaganda the Hashimites had been most successful in winning over large numbers of adherents, and Abu Muslim was only watching for a suitable moment to raise the flag of revolt. In A.H. 129 (746), on the death of Harith ibn Surayj, Nasr ibn Sayyar sent a small force from Nishapur against El-Kirmani, which was repelled, and Nasr now moved on to Merv with all the troops he could command. Abu Muslim, deeming the moment favourable for his designs, unfurled the black standard175 of the `Abbasids. Ere a month had elapsed contingents began to pour in from all quarters. Nasr, finding himself unable to check the movement, implored reinforcements from Merwan, the governor of `Irak, and pointed out that the loss of Khorasan would be fatal to the house of Umayya.

But no help arrived, and Abu Muslim, conscious of his foe’s weakness, invited El-Kirmani to join with him against Nasr; the latter, foreseeing this contingency, caused El-Kirmani to be killed by one of his soldiers, and sent his head to the Caliph. The Yemenites and the two sons of El-Kirmani attached themselves to Abu Muslim. In despair Nasr sent to Merwan a despatch in verse,176 in which he pointed out the perils surrounding his situation, and asked whether the house of Umayya was asleep or awake.

In the year A.H. 130 (747) Abu Muslim made his entry into Merv, and ordered public prayers to be offered for the `Abbasid claimant as Caliph. Nasr, who had abandoned the struggle for power and was living in retirement at Merv, withdrew on his approach to Nishapur by way of Sarakhs.177 In his flight he was joined by such of his troops as remained faithful, but near Nishapur he was overtaken and defeated by Kahtaba ibn Shebib, who had been despatched by Abu Muslim in pursuit. Nasr now fled farther westward, and on reaching Jurjan was joined by the Syrian troops from `Irak; but they came too late. Kahtaba again overtook the fugitive and inflicted a final defeat. Nasr fled towards Hamadan, but he died worn out by years and toil at Sava at the age of eighty-five. With this faithful viceroy perished the last hopes of the Umayyads, A.H. 131 (748).