Bishop of Byzantium from 198 to 211
b. 2nd century · d. 211
17th Archbishop of Constantinople (Ecumenical Patriarch)
Marcus I of Byzantium was the bishop of Byzantium for 13 years. 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.