was born in the Roman province of Moesia to low-born parents, sometime in the late 3rd century. His early professions are unknown, but it is evident that at some point he joined the military and must have greatly distinguished himself to rise through the ranks to the army's highest office, magister militum, by emperor Constans, despite being uneducated and unconnected.

He had held this command for a long period of time, and by 350