Page:William Muir, Thomas Hunter Weir - The Caliphate; Its Rise, Decline, and Fall (1915).djvu/150

637] in good truth, an empire embracing Syria, Chaldæa, and Arabia might have satisfied the ambition even of an Assyrian or Babylonian monarch. The equal mind of ʿOmar, far from being unsteadied by the flush and giddiness of victory, cared first to consolidate and secure the prize already in his hands.

Nothing now threatening on the Persian side, the ambition of Saʿd and his generals, checked by the Caliph's interdict, was for the present confined to the reduction of Mesopotamia. For this end, troops were sent up the Tigris as far as Tekrīt—a stronghold about a hundred miles above Al-Medāin, held by a mixed garrison of Greek troops and Christian Bedawīn. These bravely resisted attack. After forty days the Greeks thought to desert their native allies and escape by boat. The Bedawīn, on the other hand, gained secretly over by the Muslims, seized the water-gate; and so the Greeks, taken on both sides, were put to the sword. The column, joined by the newly converted allies, pressed forward to Mosul, which surrendered and became tributary. On the Euphrates, the Muslim arms met with equal success. The Bedawīn tribes in Mesopotamia, urged by the Byzantine court to attack the invaders then threatening Ḥimṣ, Saʿd was charged by ʿOmar to draw them off by a diversion from his side. The fortress of Hīt on the Euphrates was accordingly besieged; but it was too strong to carry by assault. Half of the force were left before the town, and the rest marched rapidly up the river to Ḳirḳīsiyā, at its junction with the Khābūr, and took it by surprise. The garrison of Hīt, when they heard of this, capitulated on condition of being allowed to retire. Thus, the lower half of Mesopotamia, from one river to the other, was reduced, the strongholds garrisoned, and the Bedawīn either converted to the Faith or brought under subjection.

From the junction of the two rivers also, downwards on either side of the Shaṭṭ al-ʿArab (the Arabian Stream) to the shores of the Persian Gulf, the rule of Islām was now thoroughly established. This tract had been exposed, with various fortune, to Arab raids ever since the invasion of Al-Muthanna. ʿOmar saw that, to secure Al-ʿIrāḳ, it was needful to occupy the head of the Gulf as far as the range of hills on its eastern side. About the period, therefore, of