iating, 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
commit no hostile act as he passed through the Roman province; but if
so, he did not keep the engagement. The city of Callinicus lay in his
way; its defences were undergoing repairs, and there was actually a gap
in one place where the old wall had been pulled down and the new one had
not yet been built. The Persian king could not resist the temptation
of seizing this easy prey; he entered the undefended town, enslaved all
whom he found in it, and then razed the place to the ground. Such is
the account which the Byzantine historian gives of the third campaign
of Chosroes against the Romans, and of the motive and manner of his
retreat. Without taxing him with falsehood, we may suspect that, for the
glorification of his favorite hero, he has kept back a portion of the
truth. The retreat of Chosroes may be ascribed with much probability to
the advance of another danger, more formidable than Belisarius, which
exactly at this time made its appearance in the country whereto he was
hastening. It was in the summer of A.D. 542 that the plague broke out at
Pelusium, and spread from that centre rapidly into the rest of Egypt and
also into Palestine. Chosroes may well have hesitated to confront this
terrible foe. He did not ultimately escape it; but he might hope to
do so, and it would clearly have been the height of imprudence to have
carried out his intention of invading Palestine when the plague was
known to be raging there.

The fourth year of the Roman war (A.D. 543) opened with a movement of
the Persian troops toward the Armenian frontier, consequent upon the
desertion of the Persian cause by the Roman Armenians in the course of
the winter. Chosroes in person once more led the attack, and proceeded
as far as Azerbijan; but, the pestilence breaking out in his army, he
hastily retreated, after some futile attempts at negotiation with the
Roman officers opposed to him. Belisarius had this year been sent to
Italy, and the Roman army of the East, amounting to thirty thousand
men, was commanded by as many as fifteen generals, almost of equal rank,
among whom t