 Theodosius's trusted general, the Frank Arbogast, was appointed magister militum for the Western provinces (bar Africa) and guardian of Valentinian.Acting in the name of Valentinian, Arbogast was actually subordinate only to Theodosius.While the general campaigned successfully on the Rhine, the young emperor remained at Vienne, in contrast to his warrior father and his older brother, who had campaigned at his age.