Heraclius advanced through Sirak to the Araxes, and, crossing the river, entered the province of Ararat. He now found himself opposed by Râhzâdh, a Persian general who was probably advancing to the relief of Tiflis. But though the Chazar auxiliaries, dismayed by the approach of winter and by the attacks of the Persians, returned to their homes, the Emperor continued his march southward through Her and Zarewand west of the Lake of Urmijah and reached the province of Atrpatakan. Pressing forward, he crossed the mountain chain which divides Media from Assyria, arriving at Chnaitha 9 Oct., where he gave his men a week's rest. Râhzâdh had meanwhile reached Ganzaca and thence followed the Emperor across the mountains, suffering severely on his march from scarcity of supplies. By 1 Dec. the Emperor reached the greater Zab and, crossing the river (i.e. marching north-west), took up his position at Nineveh. Here (12 Dec.) he won a decisive victory over Râhzâdh. The Persian general himself fell, and his troops, though not completely demoralised, were in no condition to renew the struggle. On 21 Dec. the Emperor learned that the defeated Persians had effected a junction with the reinforcements, 8000 strong, sent from the capital; he continued his southern march, however, crossing the lesser Zab (28 Dec.) and spending Christmas on the estates of the wealthy superintendent of provincial taxation, Iesdem. During the festival, acting on urgent despatches from Chosroes, the Persian army crossed the Zab higher up its course, and thus interposed a barrier between Heraclius and Ctesiphon. The Emperor on his advance found the stream of the Torna (probably the N. arm of the Nahr Wán canal) undefended, while the Persians had retreated so hurriedly that they had not even destroyed the bridge. After the passage of the Torna he reached (1 Jan. 628) Beklal (? Beit-Germa), and there learnt that Chosroes had given up his position on the Berázrúd canal, had deserted Dastagerd and fled to Ctesiphon. Dastagerd was thus occupied without a struggle and three hundred Roman standards were recovered, while the troops were greeted by numbers of those who had been carried prisoners from Edessa, Alexandria, and other cities of the Empire. On 7 Jan. Heraclius advanced from Dastagerd towards Ctesiphon, and on 10 Jan. he was only twelve miles from the Nahr Wán; but the Armenians, who had been sent forward to reconnoitre, brought back word that in face of the Persian troops it was impossible to force the passage of the canal. Heraclius after the battle of Nineveh had been, it would seem, ready to make terms, but Chosroes had rejected his overtures. In an enemy's country, with Persian troops in a strong defensive position blocking his path, with his forces in all probability much reduced and with no present opportunity of raising others, knowing that Sahrbaraz was still in command of a Persian army in the West with which he could attack his rear, while the severity of winter, though delayed, was now threatening, Heraclius was compelled to retreat. Chosroes had at least been driven to inglorious
