His father Dometius, brother of the Roman Emperor Probus, fled from Rome as a Christian during a persecution and went to Byzantium. The Bishop of Byzantium, Titus, ordained Dometius priest and, after Titus's death, Dometius became Bishop of Byzantium. After Dometius's death, his elder son Probus occupied the episcopal throne (Dometius had children from his earlier, pagan days), and Metrophanes succeeded him on his death. When the Emperor Constantine first set eyes on Metrophanes, he loved him as a father. At the time of the First Ecumenical Council, Metrophanes was a very old man and, being unable to take a full part in the Council's deliberations, appointed his assistant bishop, Alexander, as his representative. The Emperor had Metrophanes raised to the rank of Patriarch by the Council, and he thus became the first Patriarch of Constantinople. The Emperor further invited the whole Council to visit the sick and aged hierarch. When the Emperor asked him who he wished to succeed him on the patri-archal throne, Metrophanes named Alexander of Alexandria, after which he said to him: `My brother, you are my chosen successor!' He also took Archdeacon Athanasius (later Athanasius the Great, Patriarch of Alexandria) by the hand and praised him before them all. After this prophetic act, he took leave of them all and, ten days later, gave his soul to God, in 325.