Ammianus Marcellinus Res Gestae 29.5.19

[19] When these events had been spread abroad by frequent and trustworthy rumours, the officials of the province and the tribune Vincentius ¹ came out of the hiding-places in which they had taken refuge, and at last, free from fear, quickly appeared before the general. He, after having seen and received them gladly, being then still at Caesarea, inquired carefully about the true state of affairs; he learned that Firmus, under pretence of fear and submission, was secretly forming the plan of throwing our army into confusion, as if by a sudden tempest, while it feared no hostile demonstration.