On this day in A.D. 330, Constantine founded the city of Constantinople. Constantine is also known for making Christianity an accepted religion of the Roman Empire, even though he himself was not yet a Christian. He is also known for a vision (about "hoc signo vinces") that led to his conversion. For more about this Roman emperor, see:
Constantine the Great
Also on this day was celebrated the festival of the evil spirits of the dead, the Lemures. The festival was known as Lemuria.
Spirits of the Dead