He was born into a pagan family, but his father Dometius, along with all his family, became Christians and went to Byzantium to escape persecution in Rome. Dometius was ordained a priest and in time became Bishop of Byzantium. When Dometius died, his elder son Probus became Bishop; then when Probus died, Dometius' second son Metrophanes succeeded him. Metrophanes was enthroned around the time that Constantine the Great was establishing Byzantium as the new capital of the Roman Empire. He sent a delegate to the First Ecumenical Council in 325, since he was unable to attend due to age and infirmity. The Emperor Constantine loved Metrophanes as a father and urged the entire Council to visit the ailing Bishop. Ten days later he died.