St. Constantine the Great was the first Roman Emperor to be converted to Christianity after seeing a cross in the sky saying, "In this sign you shall conquer." His Edict of Milan in 313 sanctioned religious tolerance, ending the persecutions of Christians. In 330 he moved the capital from Rome, renamed it Constantinople, and established the Byzantine empire. He convened the First Ecumenical Council that laid the basis for Christianity's beliefs with the first seven articles of the Nicene Creed. Although he died in 337, and his mother, St. Helen, died in 338, they share the same feast day. Relics lay at: Mt.Athos; Panagia Tourliane Monastery, Mykonos; St. John of Ipselou Monastery, Mitilini
St. Helen, the mother of St. Constantine, made a pilgrimage to Jerusalem where she discovered, under a sweet basil plant, the cross on which Christ was crucified. She erected a shrine there and churches over Christ's tomb, his birthplace, the mountain of Ascension (Mt. of Olives), and a monastery at Mt. Sinai. She is considered one of the most important female saints in the church. She was born in 255 and died in 328.