Member of a Roman family of Constantinople. Related to Emperor Theodosius II. Ordained in 455. He lived such an austere life that he was wrongly accused of the heresy of Novatianism. Treasurer of the great church Hagia Sophia. Appointed Oikonomos, a position second only to the patriarch in authority. Gave away huge sums from his family fortune, but always anonymously so as not to draw attention to himself. Restored several churches. Composed several hymns, and was known as a miracle worker.
One day as he rushed to the consecration of a new church, he encountered a miserable, nearly naked beggar on the street. Marcian gave the man all his clothing, keeping only his chasuble. When he arrived at the church, however, he appeared to be wearing a golden robe under the chasuble; Patriarch Gennadius even rebuked Marcian for dressing so richly. The saint then pulled off the chasuble to show he was naked.