Saints Emperor Constantine and His Mother Empress Helena, Equal-to-the-Apostles made early and important contributions to the Orthodox Christian Church. They are celebrated together because Helen is Constantine's mother.
Saint Constantine the Great (†337), was a Roman emperor from AD 306 to 337 and the first to convert to Christianity. During his reign, Christianity began to transition to the dominant religion of the Roman Empire. Renouncing paganism, the Emperor did not let his capital remain in ancient Rome, the former center of the pagan realm. He transferred his capital to the East, to the city of Byzantium, which was renamed Constantinople, the city of Constantine (May 11). Constantine was deeply convinced that only Christianity could unify the immense Roman Empire with its diverse peoples.
Saint Helena, (or St. Helen) († c. 330), was the consort of the future Roman Emperor Constantius Chlorus (reigned 293-306) and the mother of the future Emperor Constantine the Great (reigned 306-337). She ranks as an important figure in the history of Christianity and of the world due to her major influence on her son. Tradition credits her with a pilgrimage to Syria Palaestina, particularly to Jerusalem, during which she allegedly discovered the True Cross. Because of her great services to the Church and her efforts in finding the Life-Creating Cross, empress Helen is called “the Equal of the Apostles.”
Saints Constantine and Helen are celebrated on the same day – May 21st of each year.