3 June 350 - Roman usurper Nepotianus, of the Constantinian dynasty, proclaims himself Roman Emperor, entering Rome at the head of a group of gladiators.

Nepotianus was the son of Eutropia, half-sister of emperor Constantine I, and of Virius Nepotianus. On his mother's part, he was grandson of Emperor Constantius Chlorus and Flavia Maximiana Theodora.

After the revolt of Magnentius, Nepotianus proclaimed himself Emperor and entered Rome with a band of gladiators on 3 June 350, which caused the urban prefect Titianus, allied to Magnentius, to flee.

Magnentius quickly dealt with the situation by sending his trusted magister officiorum Marcellinus to Rome. Nepotianus was killed in the resulting struggle (30 June 350). In the following days, Eutropia was killed too.