Ammianus Marcellinus Res Gestae 18.6.3

[3] We believe (and in fact there is no doubt of it) that Rumour flies swiftly through the paths of air, since it was through her circulation of the news of these events that the Persians held council as to their course of action. And after long debate to and fro it was decided, on the advice of Antoninus, that since Ursicinus was far away and the new commander was lightly regarded, they should give up the dangerous sieges of cities, pass the barrier of the Euphrates, and push on with the design of outstripping by speed the news of their coming and seizing upon the provinces, which in all previous wars (except in the time of Gallienus) ¹ had been untouched and had grown rich through long-continued peace; and Antoninus promised that with God’s favour he would be a most helpful leader in this enterprise.