Marcus I of Byzantium (; died 211) was the bishop of Byzantium for 13 years (198 – 211).Fordham University, History Department, Bishops/ Patriarchs of Constantinople He succeeded bishop Olympianus of Byzantium. His term of office took place during the persecution of Christians by Roman emperor Septimius Severus. His successor was Philadelphus of Byzantium.
Notes and references
Bibliography Marcus I page on Ecumenical Patriarchate website.