Before facing Magnentius, Constantius first came to terms with Vetranio, a loyal Constantian general, who had previously accepted the position of Augustus in order to retain the loyalty of his troops, and probably to stop Magnentius from gaining more support.
Before facing Magnentius, Constantius first came to terms with Vetranio, a loyal general in Illyricum who had recently been acclaimed emperor by his soldiers. Vetranio immediately sent letters to Constantius pledging his loyalty, so he probably accepted the acclamation in order to stop Magnentius from gaining more support.