Res Gestae
Ammianus Marcellinus
Ammianus Marcellinus. Ammianus Marcellinus, with an English translation, Vols. I-III. Rolfe, John C., translator. Cambridge, MA; London: Harvard University Press; W. Heinemann, 1935-1940 (printing).
During these anxious proceedings frequent and trusty messengers arrived, from whose clear and faithful reports it was learned that Julian, having in swift course passed through Italy and Illyricum, had meanwhile seized the pass of Succi, where he was awaiting auxiliaries summoned from every quarter, in order to invade Thrace attended by a great force of soldiers.
When this was known, Constantius, though overwhelmed with sorrow, was sustained by the one comforting thought, that in civil strife he had always come off victor; but while the present situation made it most difficult to decide upon a plan, he resolved, as the best course, gradually to send his soldiers on in advance in the
This plan met with general approval and the troops set out lightly equipped, as was ordered. But as he was carrying out this arrangement, word came next morning that the king with the entire force under his command had returned home, since the auspices put an end to his enterprise; relieved therefore of fear, Constantius recalled all the troops, except those that formed the usual defence of Mesopotamia, and quickly returned to the city of Nicopolis.