Decentius was the younger brother of the usurper Magnentius. Magnentius gained control of Italy, Africa and all of the west when the imperial army deserted Constans and supported him. In A.D. 351, he made Decentius Caesar and gave him command of Gaul. In A.D. 353, Constantius II`s forces regained Italy and Africa. As Magnentius` losses continued to mount, he committed suicide. Decentius hung himself eight days later.