offensive measures.  He advanced in person a day’s march beyond Nisibis, and captured the fort of Sisauranon.  Eight hundred Persian cavalry of the first class were made prisoners, and sent by Belisarius to Byzantium, where they were despatched by Justinian to Italy, where they served against the Goths.  Arethas, the chief of the Saracens who fought on the side of Rome, was sent still further in advance.  The orders given him were to cross the Tigris into Assyria, and begin to ravage it, but to return within a short time to the camp, and bring a report of the strength of the Persians beyond the river.  If the report was favorable, Belisarius intended to quit Mesopotamia, and take the whole Roman force with him into Assyria.  His plans, however, were frustrated by the selfish Arab, who, wishing to obtain the whole Assyrian spoil for himself, dismissed his Roman troops, proceeded to plunder the rich province on his own account, and sent Belisarius no intelligence of what he was so doing.  After waiting at Sisauranon till the heats of summer had decimated his army, the Roman general was compelled to retreat by the discontent of the soldiery and the representations of his principal officers.  He withdrew his forces within the Roman frontier without molestation from the enemy, and was shortly afterwards summoned to Constantinople to confer on the state of affairs with, the emperor.

The military operations of the next year (A.D. 542) were comparatively unimportant.  Chosroes collected a large army, and, repeating the movement of A.D. 540, made his appearance in Commagene early in the year, intending to press forward through Syria into Palestine, and hoping to make himself master of the sacred treasures which he knew to be accumulated in the Holy City of Jerusalem.  He found the provincial commanders, Buzes and Justus, despondent and unenterprising, declined to meet him in the field, and content to remain shut up within the walls of Hierapolis.  Had these been his only opponents the campaign would probably have proved a success; but, at the first news of his invasion, Justinian despatched Belisarius to the East, for the second time, and this able general, by his arts or by his reputation, succeeded in arresting the steps of Chosroes and frustrating his expedition.  Belisarius took up his head-quarters at Europus, on the Euphrates, a little to the south of Zeugma, and, spreading his troops on both banks of the river, appeared both to protect the Roman province and to threaten the return of the enemy.  Chosroes having sent an emissary to the Roman camp under the pretence of negotiating, but really to act the part of a spy, was so impressed (if we may believe Procopius) by the accounts which he received of the ability of the general and the warlike qualities of his soldiers, that he gave up the idea of advancing further, and was content to retire through Roman Mesopotamia into his own territories.  He is said even to have made a convention that he would