He remonstrated with Sapor, but to no purpose.
Sapor had formed the resolution to renew the contest terminated so unfavorably forty years earlier by his grandfather.

He made the emperor's interference with Persian affairs, and encouragement of his Christian subjects in their perversity, a ground of complaint, and began to threaten hostilities.

Some negotiations, which are not very clearly narrated, followed.

Both sides, apparently, had determined on war, but both wished to gain time.

It is uncertain what would have been the result had Constantine lived.