Historical Events Mar 4 Martyrdom of Saint Adrian of Nicomedia Jul 25 Constantine I is proclaimed Roman Emperor by his troops Oct 28 Maxentius proclaimed Emperor of Rome Nov 30 St Marcellus I begins his reign as Catholic Pope Famous People Who Died in 306 AD Jul 25 Constantius Chlorus, Roman Emperor (305-306 AD), dies at around 56 305 AD History by Year 307 AD