MARATONIO. — Bishop of Nicomedia, who lived in the 4th century, elevated to that see by MACEDONIUS of Constantinople (342–60) and probably deposed by the Arian party along with him and others of the Homoiousian party. He first pursued a military career, attached to the statistical office of the praetorian prefecture of Constantinople. Later he became a deacon of Constantinople and devoted himself zealously to the care of the sick and poor in hospices. Under the influence of Eustathius of Sebaste, he embraced the monastic life and founded in Constantinople a monastery of monks that still existed around the middle of the 5th century.
M. was recognized by all as a good and pious man; but his Homoiousian opinions and his loyalty to Macedonius caused him, upon becoming bishop of Nicomedia, to be a bitter persecutor of the orthodox. After the deposition and death of Macedonius, M., aiding him with his work, his money, and the prestige of his asceticism, exercised such influence in the “Macedonian” party that his followers were also called “Maratoniani.”
Historians, who from 380 onward portray Macedonius as the champion of the Spirit and interpret in this sense the name “Macedonians” commonly given to his party, also present M., more or less clearly, as the second leader of this heresy and seem to interpret similarly the name “Maratoniani” given in Constantinople to the “Macedonians.” Yet there is no evidence that M., more than Macedonius himself, explicitly concerned himself with the question of the Holy Spirit. When, not long after 366, the pneumatic opinions were certainly accepted by his colleagues in the group, such as Eustathius of Sebaste and Eleusius of Cyzicus (v. PNEUMATOMACHI), M. disappears from history.