He then started a military career serving under the "magister militum" Aetius in his campaign against the Juthungi and the Norics (430–431) and against the Burgundians (436). In 437, after being elevated to the rank of "vir illustris", he returned to Avernia, where he held a high office, probably "magister militum per Gallias". In the same year he defeated a group of Hunnic raiders near Clermont and obliged Theodoric to lift the siege of Narbonne. In 439 he became Praetorian prefect of Gaul and renewed the friendship treaty with the Visigoths.