Ammianus Marcellinus Res Gestae 26.9.3

[3] But he was met with general and obstinate resistance, for this reason in particular—that his enemy (as has been mentioned) both on the march and when they were almost in battle array, carried about with him in a litter the little daughter ¹ of Constantius, and her mother Faustina; and thereby had inflamed the passions of the soldiers to fight more bravely in defence of the imperial stock, with which he claimed that he himself was connected. Just so once the Macedonians, when on the point of engaging with the Illyrians, placed their king, who was still an infant, in his cradle behind the battle line, and from fear that he might be taken prisoner, beat down their adversaries with greater valour. ²