Persia had recovered from it the portion of Media Atropatene ceded by the treaty between Galerius and Narses.

Sapor, therefore, had nothing to fear on this side; and he might reasonably expect to find friends among the Armenians themselves, should the general position of his affairs allow him to make an effort to extend Persian influence once more over the Armenian highland.
The bands of Sapor crossed the Roman frontier soon after, if not even before, the death of Constantine; and after an interval of forty years the two great powers of the world were once more engaged in a bloody conflict.

Constantius, having paid the last honors to his father's remains, hastened to the eastern frontier, where he found the Roman army weak in numbers, badly armed and badly provided, ill-disposed towards himself, and almost ready to mutiny.

It was necessary, before anything could be done to resist the advance of Sapor, that the insubordination of the troops should be checked, their wants supplied, and their good-will conciliated.

Constantius applied himself to effect these changes.