After Maurice had been overthrown by a mutiny and slain, and the vile Phocas elevated to the imperial throne (November, 602), Chosroes looked upon himself as in a state of war against the Romans, in the capacity of avenger of his “father” Maurice, and protector of his putative son Theodosius, who had taken refuge with him. Furthermore Narses, who was in command at Edessa, appealed to him against Phocas. Chosroes, therefore, made a beginning by imprisoning the ambassadors by whose hand Phocas informed him of his accession. The actual war probably commenced at the beginning of 604. For twenty years the Roman Empire was overrun by Persian armies as it never had been before, so disordered was it by Phocas, so harassed by Avars and other barbarous tribes. Chosroes was present in person at the taking of Dara, after which he took no active part in the war. In a few years the Persian armies had pressed forward far on the road to Asia Minor, even reaching Chalcedon, opposite Constantinople. The fact that the power of the Persian Empire was not very firmly based for all that, is shown by an event, in itself insignificant, which falls within this period (between 604 and 610), the battle of Dhu Kar. Chosroes had abolished the kingdom of Hira, and caused Nohman, the last king, to be put to death. By this means the empire was quit of a vassal state which had often proved troublesome; but, on the other hand, it was henceforward far more difficult to gain an ascendency over the savage tribes of the desert, and prevent them from making raids upon the cultivated regions. After the fall of Nohman, the Bedouin tribes of Bekr ben Wail succeeded in inflicting a total defeat on an imperial army consisting of Arabs and Persian regular troops at Dhu Kar, not far from the Euphrates and a few days’ march from Ctesiphon, and holding the territory out of which the Persians wished to drive them. This victory of Arabs over Persians, magnified by national vanity, greatly encouraged the former in their self-esteem, and strengthened the confidence of the Moslems when they attacked the empire. CONFLICT WITH HERACLIUS; FALL OF CHOSROES II [Sidenote: [610-628 A.D.]]