The Moslems, however, were soon close at hand. The Bekr Bedouins had made raids upon the royal dominions several times since the battle of Dhu Kar. After a while Muthanna, one of their bravest chiefs, became a convert to Islam, and with that force behind them their attacks grew bolder. Then (probably in 633) the mighty Khalid, after subduing the insurrections in Arabia, appeared with a small force on the lower Euphrates to conduct the operations of these same Bedouins. Persian Arabs and imperial troops were defeated in small engagements, and soon a number of border forts were in the hands of the Moslems. The inhabitants of the regions west of the Euphrates, who were all Christians, and, like all the Christians about the Euphrates and Tigris, felt little loyalty to the empire, submitted to the victors and even undertook to supply them with information.
ARAB INCURSIONS
[633-637 A.D.]
The Arabs were already beginning to rove on the far side of the Euphrates; they plundered Baghdad, then a village, while a fair was being held there, as well as other places on the right bank of the Tigris. But Khalid presently received orders (the commencement of the summer of 634) to start for Syria, the conquest of which was at the time a matter of greater consequence to the caliph. His successor, Abu Obaid of Taif, brought some reinforcements with him; but when at length a regular Persian army came on the scene, the Moslems, in spite of their heroic valour, were completely defeated in the “battle of the Bridge,” on the Euphrates, November 26th, 634. After their leader had fallen Muthanna had great difficulty in extricating the remains of his army. Most of the Moslem conquests were lost without further ado. After some hesitation Omar (caliph since August 23rd, 634) resolved to send more troops to Irak. He appealed simultaneously to the greed and piety of the Arabs, urging them in the same breath to win the treasures of Chosroes and the joys of paradise. A larger Persian army was now defeated for the first time (at Buwaib, 635 or 636); the commander, a member of the house of Mihran, was among the slain.
The Arabs were once more masters of the country west of the Euphrates. They found an energetic and cautious leader in Saad, son of Abu Wakkas, one of the first followers of the prophet. The lords at Ctesiphon now realised the great danger that impended over the empire. The news of the battle on the Yarmuk (August 20th, 636) which cost Heraclius, the conqueror of Persia, the whole of Syria, probably contributed to their fears. Rustem, therefore, took the head of a great army in person. As a token of the gravity of the struggle he bore with him the sacred banner of the empire (dirafshi Kaviyan), which was supposed to have come down from time immemorial. He also took with him a number of elephants, according to the Persian usage in war. At the approach of the advanced guard of the Persian army Saad evacuated his position and retreated to Kadisiya, on the verge of the desert (south or southwest of Hira). For months the armies confronted one another, with only a little space between. The Arabic force was certainly much the smaller of the two; they could not have fed a large army in that place, for they were dependent on the produce of their raids and such provisions as the caliph sent after them from Medina.
At length the great battle of Kadisiya (end of 636 or 637) was fought. It lasted for several days; Saad was ill, but nevertheless took the command. The Persians were, for the most part, much better armed than the Arabs, but the courage of the latter was wound up to the highest pitch. They were terrified by the elephants at first, but as they pressed on gallantly for all their fears, the animals appear to have got beyond control and to have become a source of confusion to the Persian ranks. The great majority of the Persians certainly behaved with cowardice, after their ancient fashion; but the Arabs had hard work before the foe was defeated, Rustem himself slain, and the banner of the Persian Empire taken.
ARAB CONQUEST
[637-652 A.D.]
The battle of Kadisiya practically decided the fate of the provinces on the Tigris. There were a few other fights, some of them in the vast territory of ancient Babylon, but the Arabs soon afterwards reached Seleucia, took it after a protracted siege, crossed the rapid stream of the Tigris, and quickly forced their way into Ctesiphon. The young king Yezdegerd had already fled to Holwan (on the border between Babylonia and Media). On their way thither, at Jalula, the Arabs won another victory over the Persians under Khorrezadh, Rustem’s brother, and Yezdegerd fled further into the interior. Meanwhile other Arabs had conquered the delta of the stream and thence advanced into Susiana. A very able resolute commander might still have saved the actual land of Iran for the Persians. Omar, who was very cautious in spite of his energy, was apprehensive lest the Arabs should extend their forces too far, and at first would not give orders for an advance into the highlands. At length he did so. A great Persian army had been collected at Nehavend, a little to the south of the ancient highway from Babylon to Ecbatana. Here a great battle was fought (in 640, 641, or 642), in which the Arabs—first under the command of Nohman and, after he had fallen, under Hudhaifa the Meccan—won a brilliant victory.