Magnentius

Magnus Magnentius (c. 303 – 10 August 353) was a Roman general and usurper against Constantius II. Of Germanic descent, Magnentius served with distinction in Gaul, where the army chose him as a replacement for the unpopular emperor Constans. Acclaimed Augustus on 18 January 350, Magnentius quickly killed Constans and gained control over most of the Western Empire. The Eastern emperor Constantius II, brother of Constans, refused to acknowledge Magnentius's legitimacy, leading to three years of civil war. Decisively defeated at the Battle of Mons Seleucus, Magnentius killed himself on 10 August 353.

Much of Magnentius's short reign was concerned with asserting his legitimacy. Unlike Constans, Magnentius was unrelated to Constantine the Great, and so had no dynastic claim to the emperorship. Magnentius instead sought popular support by modeling himself as a liberator who had freed the Western Empire from the tyranny of Constans. He attempted various public and religious reforms, but almost all his acts were quickly repealed by Constantius after his death. Though Magnentius was accepted as emperor by the Western provinces, Magnentius's reign was condemned as an illegitimate barbarian usurpation by the succeeding Constantinian government. This, together with his failure to neutralize the civil war against him, has led to modern historians designation Magnentius as a usurper or "usurping emperor" rather than a full emperor in the ordinary imperial succession.