- Early in 350 AD, Magnetius revolted against Constans, who was murdered, leaving Magnetius master of Gaul, Britain, Spain, Africa, and Italy.
- The soldiers of the Illyrian army were undecided as to whether they should support Magnentius, or express their allegiance to Constantius II. They were persuaded by Constantia, the sister of Constantius to proclaim their commander, Vetranio, emperor.
- Vetranio immediately proclaimed his loyalty to Constantius, and kept Magnentius at bay whilst Constantius was settling the affairs of the East.
- After Vetranio had re-claimed Illyricum, Constantius arrived to take command, and Vetranio formally abdicated in his presence.
- Vetranio was granted an estate at Prusa in Bithynia where he spent the last six years of his life in comfort, one of the few emperors not to die a violent death.