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.
Read More about Nepotianus in Harpers Dictionary of Classical Antiquities