The Ecclesiastical History Of Theodoret by Theodoret
Chapter XIV.--Of the information given by Maximus the tyrant to Valentinianus.
After a considerable time Maximus was informed of the attacks which were being made upon the loud-voiced herald of the truth, and he sent dispatches to Valentinianus charging him to put a stop to his war against true religion and exhorting him not to abandon his father's faith. In the event of his advice being disregarded he further threatened war, and confirmed what he wrote by what he did, for he mustered his forces and marched for Milan where Valentinianus was then residing. When the latter heard of his approach he fled into Illyricum. He had learnt by experience what good he had got by following his mother's advice.