“Yazdejird, Persarum rex.... Rostamum misit oppugnatum Saadum... neque unquam belloram et dissentionum expers fuit, donee oecideretur. Regnavit autem annos viginti.”—Eutychius, Annales, vol. ii. pp. 295-6.
The power which Mohammed had so rapidly built up fell to pieces at his decease. Isdigerd can scarcely have been well settled upon this throne when the welcome tidings must have reached him that the Prophet was dead, that the Arabs generally were in revolt, that Al Mondar had renounced Islamism and resumed a position of independence. For the time Mohammedanism was struck down. It remained to be seen whether the movement had derived its strength solely from the genius of the Prophet, or whether minds of inferior calibre would suffice to renew and sustain the impulse which had proceeded from him, and which under him had proved of such wonderful force and efficacy.
The companions of Mohammed lost no time in appointing his successor. Their choice fell upon Abu-bekr, his friend and father-in-law, who was a person of an energetic character, brave, chaste, and temperate. Abu-bekr proved himself quite equal to the difficulties of the situation. Being unfit for war himself, as he was above sixty years of age, he employed able generals, and within a few months of his accession struck such a series of blows that rebellion collapsed everywhere, and in a short time the whole Arab nation, except the tribe of Gassan, acknowledged themselves his subjects. Among the rivals against whom he measured himself, the most important was Moseilama. Moseilama, who affected the prophetic character, had a numerous following, and was able to fight a pitched battle with the forces of Abu-bekr, which numbered 40,000 men. At the first encounter he even succeeded in repulsing this considerable army, which lost 1200 warriors; but in a second engagement the Mohammedans were victorious—Moseilama was slain—and Kaled, “the Sword of God,” carried back to Medina the news of his own triumph, and the spoils of the defeated enemy. Soon after the fall of Moseilama, the tribes still in rebellion submitted themselves, and the first of the Caliphs found himself at liberty to enter upon schemes of foreign conquest.
Distracted between the temptations offered to his arms by the East and by the West, Abu-bekr in his first year (A.D. 633) sent expeditions in both directions, against Syria, and against Hira, where Iyas, the Persian feudatory, who had succeeded Noman, son of Al Mondar, held his court, on the western branch of the Euphrates. For this latter expedition the commander selected was the irresistible Kaled, who marched a body of 2000 men across the desert to the branch stream,s which he reached in about latitude 30°. Assisted by Al Mothanna, chief of the Beni Sheiban, who had been a subject of Iyas, but had revolted and placed himself under the protection of Abu-bekr, Kaled rapidly reduced the kingdom of Hira, took successively Banikiya, Barasuilia, and El Lis, descended the river to the capital, and there fought an important battle with the combined Persian and Arab forces, the first trial of arms between the followers of Mohammed and those of Zoroaster. The Persian force consisted entirely of horse, and was commanded by a general whom the Arab writers call Asadsubeh. Their number is not mentioned, but was probably small. Charged furiously by Al Mothanna, they immediately broke and fled; Hira was left with no other protection than its walls; and Iyas, yielding to necessity, made his submission to the conqueror, and consented to pay a tribute of 290,000 dirhems.
The splendid success of his pioneer induced Abu-bekr to support the war in this quarter with vigor. Reinforcements joined Kaled from every side, and in a short time he found himself at the head of an army of 18,000 men. With this force he proceeded southwards bent on reducing the entire tract between the desert and the Eastern or real Euphrates. The most important city of the southern region was at the time Obolla which was situated on a canal or backwater derived from the Euphrates, not far from the modern Busrah. It was the great emporium for the Indian trade, and was known as the limes Indorum or “frontier city towards India.” The Persian governor was a certain Hormuz or Hormisdas who held the post with 20,000 men. Kaled fought his second great battle with this antagonist, and was once more completely victorious, killing Hormuz, according to the Arabian accounts, with his own hands. Obolla surrendered; a vast booty was taken; and, after liberally rewarding his soldiers Kaled sent the fifth part of the spoils, together with a captured elephant, to Abu-bekr at Medina. The strange animal astonished the simple natives, who asked one another wonderingly “Is this indeed one of God’s works, or did human art make it.”
The victories of Kaled Over Asadsubeh and Hormuz were followed by a number of other successes, the entire result being that the whole of the fertile region on the right bank of the Euphrates from Hit to the Persian Gulf, was for the time reduced, made a portion of Ahu-bekr’s dominions, and parcelled out among Mohammedan governors. Persia was deprived of the protection which a dependent Arab kingdom to the west of the river had hitherto afforded her, and was brought into direct contact with the great Mohammedan monarchy along almost the whole of her western frontier. Henceforth she was open to attack on this side for a distance of above four hundred miles, with no better barrier than a couple of rivers interposed between her enemy and her capital.
Soon after his conquest of the kingdom of Hira, Kaled was recalled from the Euphrates to the Syrian war, and was employed in the siege of Damascus, while Persia enjoyed a breathing-space. Advantage was taken of this interval to stir up disaffection in the newly-conquered province. Rustam appointed to the command against the Arabs by Isdigerd sent emissaries to the various towns of the Sawad, urging them to rise in revolt and promising to support such a movement with a Persian army. The situation was critical; and if the Mohammedans had been less tenacious, or the Persians more skilfully handled, the whole of the Sawad might have been recovered. But Rustam allowed his troops to be defeated in detail. Al Mothanna and Abu Obediah, in three separate engagements, at Namarik, Sakatiya, and Barusma, overcame the Persian leaders, Jaban, Narses, and Jalenus, and drove their shattered armies back on the Tigris. The Mohammedan authority was completely re-established in the tract between the desert and the Euphrates; it was even extended across the Euphrates into the tract watered by the Shat-el-Hie; and it soon became a question whether Persia would be able to hold the Mesopotamian region, or whether the irrepressible Arabs would not very shortly wrest it from her grasp. But at this point in the history the Arabs experienced a severe reverse. On learning the defeat of his lieutenants, Rustam sent an army to watch the enemy, under the command of Bahman-Dsul-hadjib, or “Bahman the beetle-browed,” which encamped upon the Western Euphrates at Kossen-natek, not far from the site of Kufa. At the same time, to raise the courage of the soldiers, he entrusted to this leader the sacred standard of Persia, the famous durufsh-kawani, or leathern apron of the blacksmith Kawah, which was richly adorned with silk and gems, and is said to have measured, eighteen feet long by twelve feet broad. Bahman had with him, according to the Persian tradition, 30,000 men and thirty elephants; the Arabs under Abu Obediah numbered no more than 9000, or at the most 10,000. Bahman is reported to have given his adversary the alternative of passing the Euphrates or allowing the Persians to cross it. Abu Obediah preferred the bolder course, and, in spite of the dissuasions of his chief officers, threw a bridge of boats across the stream, and so conveyed his troops to the left bank. Here he found the Persian horse-archers covered with their scale armor, and drawn up in a solid line behind their elephants. Galled severely by the successive flights of arrows, the Arab cavalry sought to come to close quarters; but their horses, terrified by the unwonted sight of the huge animals, and further alarmed by the tinkling of the bells hung round their necks, refused to advance. It was found necessary to dismount, and assail the Persian line on foot. A considerable impression had been made, and it was thought that the Persians would take to flight, when Abu Obediah, in attacking the most conspicuous of the elephants, was seized by the infuriated animal and trampled under his feet. Inspirited by this success, the Persians rushed upon their enemies, who, disheartened by the loss of their commander, began a retrograde movement, falling back upon their newly-made bridge. This, however, was found to have been broken, either by the enemy, or by a rash Arab who thought, by making retreat impossible, to give his own side the courage of despair. Before the damage done could be repaired, the retreating host suffered severely. The Persians pressed closely upon them, slew many, and drove others into the stream, where they were drowned. Out of the 9000 or 10,000 who originally passed the river, only 5000 returned, and of these 2000 at once dispersed to their homes. Besides Abu Obediah, the veteran Salit was slain; and Al Mothanna, who succeeded to the command on Abu Obediah’s death, was severely wounded. The last remnant of the defeated army might easily have been destroyed, had not a dissension arisen among the Persians, which induced Bahman to return to Otesiphon.
The Arabs, upon this repulse, retired to El Lis; and Al Mothanna sent to Omar for reinforcements, which speedily arrived under the command of Jarir, son of Abdallah. Al Mothanna was preparing to resume the offensive when the Persians anticipated him. A body of picked troops, led by Mihran a general of reputation, crossed the Euphrates, and made a dash at Hira. Hastily collecting his men, who were widely dispersed, Al Mothanna gave the assailants battle on the canal El Boweib, in the near vicinity of the threatened town, and though the Persians fought with desperation from noon to sunset, succeeded in defeating them and in killing their commander. The beaten army recrossed the Euphrates, and returned to Otesiphon without suffering further losses, since the Arabs were content to have baffled their attack, and did not pursue them many miles from the field of battle. All Mesopotamia, however, was by this defeat laid open to the invaders, whose ravages soon extended to the Tigris and the near vicinity of the capital.
The year A.D. 636 now arrived, and the Persians resolved upon an extraordinary effort. An army of 120,000 men was enrolled, and Rustam, reckoned the best general of the day, was placed at its head. The Euphrates was once more crossed, the Sawad entered, its inhabitants invited to revolt, and the Arab force, which had been concentrated at Cadesia (Kadisiyeh), where it rested upon a fortified town, was sought out and challenged to the combat. The Caliph Omar had by great efforts contrived to raise his troops in the Sawad to the number of 30,000, and had entrusted the command of them to Sa’ad, the son of Wakas, since Al Mothanna had died of his wound. Sa’ad stood wholly on the defensive. His camp was pitched outside the walls of Cadesia, in a position protected on either side by a canal, or branch stream, derived from the Euphrates, and flowing to the south-east out of the Sea of Nedjef. He himself, prevented by boils from sitting on his horse, looked down on his troops, and sent them directions from the Oadesian citadel. Rustam, in order to come to blows, was obliged to fill up the more eastern of the branch streams (El Atik), with reeds and earth, and in this way to cross the channel. The Arabs made no attempt to hinder the operation; and the Persian general, having brought his vast army directly opposite to the enemy, proceeded to array his troops as he thought most expedient. Dividing his army into a centre and two wings, he took himself the position of honor in, the mid-line with nineteen elephants and three fifths of his forces, while he gave the command of the right wing to Jalenus, and of the left to Bendsuwan; each of whom we may suppose to have had 24,000 troops and seven elephants. The Arabs, on their side, made no such division. Kaled, son of Orfuta, was the sole leader in the fight, though Sa’ad from his watch-tower observed the battle and gave his orders. The engagement began at mid-day and continued till sunset. At the signal of Allah akbar, “God is great,” shouted by Sa’ad from his tower, the Arabs rushed to the attack. Their cavalry charged; but the Persians advanced against them their line of elephants, repeating with excellent effect the tactics of the famous “Battle of the Bridge.” The Arab horse fled; the foot alone remained firm; victory seemed inclining to the Persians, who were especially successful on either wing; Toleicha, with his “lions” failed to re-establish the balance; and all would have been lost, had not Assem, at the command of Sa’ad, sent a body of archers and other footmen to close with the elephants, gall them with missiles, cut their girths, and so precipitate their riders to the ground. Relieved from this danger, the Arab horse succeeded in repulsing the Persians, who as evening approached retired in good order to their camp. The chief loss on this, the “day of concussion,” was suffered by the Arabs, who admit that they had 500 killed, and must have had a proportional number of wounded.
On the morning of the second day the site of the battle was somewhat changed, the Persians having retired a little during the night. Reinforcements from Syria kept reaching the Arab camp through most of the day; and hence it is known to the Arab writers as the “day of succors.” The engagement seems for some time not to have been general, the Arabs waiting for more troops to reach them, while the Persians abstained because they had not yet repaired the furniture of their elephants. Thus the morning passed in light skirmishes and single combats between the champions of either host, who went out singly before the lines and challenged each other to the encounter. The result of the duels was adverse to the Persians, who lost in the course of them two of their best generals, Bendsuwan and Bahman-Dsulhadjib. After a time the Arabs, regarding themselves as sufficiently reinforced, attacked the Persians along their whole line, partly with horse, and partly with camels, dressed up to resemble elephants. The effect on the Persian cavalry was the same as had on the preceding day been produced by the real elephants on the horse of the Arabs; it was driven off the field and dispersed, suffering considerable losses. But the infantry stood firm, and after a while the cavalry rallied; Rustam, who had been in danger of suffering capture, was saved; and night closing in, defeat was avoided, though the advantage of the day rested clearly with the Arabs. The Persians had lost 10,000 in killed and wounded, the Arabs no more than 2000.