15. Pacatus (xii. 28) celebrates his fidelity; while his
treachery is marked in Prosper's Chronicle as the cause of
the ruin of Gratian. Ambrose who has occasion to exculpate
himself, only condemns the death of Vallio, a faithful
servant of Gratian (tom. ii. Epist. xxiv. p. 891, edit.
Benedict.).