Nepotianus in Harpers Dictionary of Classical Antiquities

A son of Eutropia, the half-sister of the emperor Constantine. He proclaimed himself emperor (A.D. 350) after the death of his cousin Constans, marched to Rome with a body of gladiators and other disreputable followers, defeated Anicetus, the praetorian prefect, and pillaged the city. He enjoyed his usurped power only twenty-eight days, at the end of which period he was defeated and slain by Marcellinus, one of the lieutenants of Magnentius.