His lieutenant in Mesopotamia had meant well in opening a negotiation with a Persian governor; but he had acted without orders, and could not bind his master.

Nevertheless, he (Constantius) would not disclaim what had been done, since he did not object to a peace, provided it were fair and honorable.

But to ask the master of the whole Roman world to surrender territories which he had successfully defended when he ruled only over the provinces of the East was plainly indecent and absurd.

He must add that the employment of threats was futile, and too common an artifice; more especially as the Persians themselves must know that Rome always defended herself when attacked, and that, if occasionally she was vanquished in a battle, yet she never failed to have the advantage in the event of every war." Three envoys were entrusted with the delivery of this reply--Prosper, a count of the empire; Spectatus, a tribune and notary; and Eustathius, an orator and philosopher, a pupil of the celebrated Neo-Platonist, Jamblichus, and a friend of St.Basil.
Constantius was most anxious for peace, as a dangerous war threatened with the Alemanni, one of the most powerful tribes of Germany.

He seems to have hoped that, if the unadorned language of the two statesmen failed to move Sapor, he might be won over by the persuasive eloquence of the professor of rhetoric.
But Sapor was bent on war.