The confusion and troubles which afflicted the Roman Empire at this time were such as might well give him hopes of obtaining a decided advantage.
Alexander, his father's adversary, had been murdered in A.D.235 by Maximin, who from the condition of a Thracian peasant had risen into the higher ranks of the army.

The upstart had ruled like the savage that he was; and, after three years of misery, the whole Roman world had risen against him.

Two emperors had been proclaimed in Africa; on their fall, two others had been elected by the Senate; a third, a mere boy, had been added at the demand of the Roman populace.

All the pretenders except the last had met with violent deaths; and, after the shocks of a year unparalleled since A.D.69, the administration of the greatest kingdom in the world was in the hands of a youth of fifteen.

Sapor, no doubt, thought he saw in this condition of things an opportunity that he ought not to miss, and rapidly matured his plans lest the favorable moment should pass away.
Crossing the middle Tigris into Mesopotamia, the bands of Sapor first attacked the important city of Nisibis.