speedily founded at Cordova the Western Omayyad Caliphate (see Spain: History).
While Mansur was thus losing Africa and Spain, he was trying to redeem the losses the empire had sustained on the northern frontier by the Byzantines. In 750–751 the emperor Constantine V. (Copronymus) had unsuccessfully blockaded Malatia; but five years later he took it by force and razed its wall to the ground. Mansur now sent in 757 an army of 70,000 men under the command of his cousin Abdalwahhāb, the son of Ibrāhīm the Imam, whom he had made governor of Mesopotamia, the real chief being Hasan b. Qaḥṭaba. They rebuilt all that the emperor had destroyed, and made this key of Asia Minor stronger than ever before. The Moslems then made a raid by the pass of Ḥadath (Adata) and invaded the land of the Byzantines. Two aunts of the caliph took part in this expedition, having made a vow that if the dominion of the Omayyads were ended they would wage war in the path of God. Constantine advanced with a numerous army, but was afraid of attacking the invaders. The Moslems also rebuilt Mopsuestia. But from 758 till 763 Mansur was so occupied with his own affairs that he could not think of further raids.
In 758 (others say in 753 or 754) a body of 600 sectaries, called Rāwendīs (q.v.), went to Hāshimīya, the residence of the caliph, not far from Kufa. They believed that the caliph was their lord, to whom they owed their daily bread, and came to pay him divine honours. They began by marching in solemn procession round the palace, as if it had been the Kaʽba. Mansur being told of it said: “I would rather they went to hell in obedience to us, than to heaven in disobedience.” But as they grew tumultuous, and he saw that this impious homage gave offence to his men, he caused the principal leaders to be seized and thrown into prison. The Rāwendīs immediately rose in revolt, broke the prison doors, rescued their chiefs, and returned to the palace. The unfortunate fanatics were hunted down and massacred to the last man, and thereby the ties that bound the Abbasids to the ultra-Shiʽites were severed. From that time forward the Abbasid caliphs became the maintainers of orthodox Islam, just as the Omayyads had been. The name of Hāshimīya, which the reigning family still retained, was henceforward derived not from Abu Hāshim, but from Hāshim, the grandfather of Abbas, the great-grandfather of the Prophet.
A much greater danger now threatened Mansur. In the last days of the Omayyads, the Shiʽites had chosen as caliph, Mahommed b. Abdallah b. Hasan, whom they called the Mahdi and the “pure soul,” and Mansur had been among those who pledged themselves to him by oath. Not unnaturally, the Alids in Medina were indignant at being supplanted by the Abbasids, and Mansur’s chief concern was to get Mahommed into his power. Immediately after his occupying the throne, he named Ziyād b. Obaidallah governor of Medina, with orders to lay hands on Mahommed and his brother Ibrāhīm, who, warned betimes, took refuge in flight. In 758 Mansur, informed that a revolt was in preparation, came himself to Medina and ordered Abdallah to tell him where his sons were. As he could not or would not tell, he together with all his brothers and some other relatives were seized and transported to Irak, where Abdallah and his brother Ali were beheaded and the others imprisoned. Notwithstanding all these precautions, a vast conspiracy was formed. On the same day Mahommed was to raise the standard of revolt in Medina, Ibrāhīm in Baṣra. But the Alids, though not devoid of personal courage, never excelled in politics or in tactics. In A.D. 762 Mahommed took Medina and had himself proclaimed caliph. The governor of Kufa, ʽIsā b. Mūsā, received orders to march against him, entered Arabia, and captured Medina, which, fortified by Mahommed by the same means as the Prophet had employed against the besieging Meccans, could not hold out against the well-trained Khorasanians. Mahommed was defeated and slain. His head was cut off and sent to Mansur. When on the point of death, Mahommed gave the famous sword of the Prophet called Dhuʽl-Fiqār to a merchant to whom he owed 400 dinars. It came later into the possession of Harun al-Rashid. In the meanwhile Ibrāhīm had not only gained possession of Baṣra, Ahwāz and Fārs, but had even occupied Wāsit. The empire of the Abbasids was in great jeopardy. For fifty days Mansur stayed in his room, neither changing his clothes nor allowing himself a moment’s repose. The greater part of his troops were in Rei with his son al-Mahdi, who had conquered Tabaristan, in Africa, with Mahommed b. Ashʽath, and in Arabia with ʽĪsā b. Mūsā. Had Ibrāhīm marched at once against Kufa he might have crushed Mansur, but he let slip the opportunity. A terrible conflict took place at Bā-Khamra, 48 m. from Kufa. Ḥomaid b. Qaḥṭaba, the commander of Mansur’s army, was defeated, only a small division under ʽĪsā b. Mūsā holding its ground. At that moment Salm, the son of the famous Qotaiba b. Moslim, came to the rescue by attacking the rear of Ibrāhīm. Ḥomaid rallied his troops, and Ibrāhīm was overpowered. At last he fell, pierced by an arrow, and, in spite of the desperate efforts of his followers, his body remained in the hands of the enemy. His head was cut off and brought to Mansur.
Mansur could now give his mind to the founding of the new capital. When the tumult of the Rāwendīs took place he saw clearly that his personal safety was not assured in Hāshimīya,[1] where a riot of the populace could be very dangerous, and his troops were continually exposed to the perverting influence of the fickle and disloyal citizens of Kufa. He had just made choice of the admirable site of the old market-town of Bagdad when the tidings came of the rising of Mahommed in Medina. In those days he saw that he had been very imprudent to denude himself of troops, and decided to keep henceforth always with him a body of 30,000 soldiers. So Bagdad, or properly “the round city” of Mansur, on the western bank of the Tigris, was built as the capital. Strictly it was a huge citadel, in the centre of which was the palace of the caliph and the great mosque. But around this nucleus there soon grew up the great metropolis which was to be the centre of the civilized world as long as the Caliphate lasted.[2] The building lasted three years and was completed in the year 149 (A.D. 766). That year is really the beginning of the new era. “The Omayyads,” says the Spanish writer Ibn Ḥazm, “were an Arabic dynasty; they had no fortified residence, nor citadel; each of them dwelt in his villa, where he lived before becoming caliph; they did not desire that the Moslems should speak to them as slaves to their master, nor kiss the ground before them or their feet; they only gave their care to the appointment of able governors in the provinces of the empire. The Abbasids, on the contrary, were a Persian dynasty, under which the Arab tribal system, as regulated by Omar, fell to pieces; the Persians of Khorasan were the real rulers, and the government became despotic as in the days of Chrosroes.” The reign of Abuʽl-Abbas and the first part of that of Mansur had been almost a continuation of the former period. But now his equals in birth and rank, the Omayyads and the Alids, had been crushed; the principal actors in the great struggle, the leaders of the propaganda and Abu Moslim were out of the way; the caliph stood far above all his subjects; and his only possible antagonists were the members of his own family.
ʽĪsā b. Mūsā had been designated, as we have seen, by Abuʽl-Abbas as successor to Mansur. The latter having vainly tried to compel ʽĪsā to renounce his right of succession, in favour of Mansur’s son Mahommed al-Mahdi, produced false witnesses who swore that he had done so. However unwillingly, ʽĪsā was obliged at last to yield, but it was understood that, in case of Mahommed’s death, the succession should return to ʽĪsā. One of the false witnesses was, it is asserted, Khālid b. Barmak, the head of that celebrated family the Barmecides (q.v.), which played so important a part in the reign of Harun al-Rashid. This Khālid, who was descended from an old sacerdotal family in Balkh, and had been one of the trusty supporters of Abu Moslim, Mansur appointed as minister of finance.
A son of Mahommed the Alid had escaped to India, where,
