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