Ammianus Marcellinus Res Gestae 24.4.24

[24] It was thought that Mars himself (if it is lawful for the majesty of the gods to mingle with mortals) had been with Luscinus, ¹ when he stormed the camp of the Lucanians; and this was believed because in the heat of battle an armed warrior of formidable size was seen carrying scaling-ladders, and on the following day, when the army was reviewed, could not be found, although he was sought for with particular care; whereas, if he had been a soldier, from consciousness of a memorable exploit he would have presented himself of his own accord. But although then the doer of that noble deed was wholly unknown, on the present occasion those who had fought valiantly were made conspicuous by gifts of siege-crowns, ² and according to the ancient custom were commended in the presence of the assembled army.