Justinian’s reign opened with a fierce war with the old Persian king Kobad. The struggle which this monarch had waged with Anastasius, twenty-five years before, had been so indecisive that the Sassanian longed for a new trial of arms. Almost immediately on Justinian’s accession he issued his declaration of war, using as a pretext the erection of some fortifications near Nisibis, which were being constructed by Belisarius, governor of Daras, a young officer whose name was destined to be intimately associated with the whole history of Justinian’s reign. [Sidenote: First war with Persia, 528-31.] The war opened with a defeat in the open field, suffered by the Roman army of Mesopotamia; but when reinforcements came up the Persians retreated beyond their frontier. After the winter of 528-29 was over neither side advanced in force, and all that occurred was a flying Roman raid into Assyria, and an equally hasty Persian incursion into Syria, both of which did some harm, but had no practical result on the fate of the war. Things went far otherwise in the next year, 530: the Persians crossed the frontier in full force, and marched on Daras, where they were met by Belisarius, who had lately been appointed commander-in-chief in the East. Under the walls of Daras the decisive battle of the war was fought, in which Belisarius, with 25,000 men, defeated 40,000 Persians by means of his tactical skill. The plan which he worked was to draw back his centre, containing all the Roman infantry, and when the Persians followed it, to launch against their exposed flanks all his cavalry, a miscellaneous gathering of Hunnish light horse, Teutonic Heruli from the Danube, and Roman _Cataphracti_ or cuirassiers. This plan, much resembling Hannibal’s manœuvre at Cannae, and perhaps consciously copied from it, resulted in the complete rout of the Sassanian host. After this defeat Kobad commenced abortive negotiations for peace, but the war was protracted into the next year, and Belisarius did not fare so well in 531. In stopping a Persian raiding force on the middle Euphrates, which aimed at Syria, and had turned the southern flank of the Mesopotamian fortresses, he suffered serious loss at the affair of Callinicum. Though he was defeated, his resistance had yet turned and frustrated the Persian expedition. Four months later king Kobad died, and his successor Chosroes I. made peace on the base of the _status quo ante_, fearing to continue the Roman war while his throne was insecure. (September, 531.)