Res Gestae

Also, to give greater strength to this principle, Julian often repeated the saying of the lyric poet Bacchylides, whom he delighted to read, who declares that as a skilful painter gives a face beauty, just so chastity gives charm to a life of high aims. This blemish in the mature strength of manhood he avoided with such care, that even his most confidential attendants never (as often happens) accused him even of a suspicion of any lustfulness.

Moreover, this kind of self-restraint was made still greater through his moderation in eating and sleeping, which he strictly observed at home and abroad. For in time of peace the frugality of his living and his table excited the wonder of those who could judge aright, as if he intended soon to resume the philosopher’s cloak. And on his various campaigns, he was often seen partaking of common and scanty food, sometimes standing up like a common soldier.