 He chose to accept Maximus as emperor in the west, with the sole stipulation that young Valentinian II, (represented, for reason of his extreme youth, by his mother Justina) be permitted to rule as an independent third Augustus in Italy; Maximus accepted, and war was for the time avoided.Four years later (387), after Justina had alienated Italy by her Arianism and her religious conflicts with the popular bishop Ambrose of Milan, Maximus saw his opportunity to complete his usurpation of the west by conquering Italy from the 16 year-old Valentinian.To effect this most easily, he employed the pretense of reinforcing the Rhaetian frontier against the barbarians to introduce his troops over the Alps into Italy, after which, with the passes secure behind him, he treacherously turned to march on Milan, Valentinian's capital.