EUSEBIUS of DORYLEUM. - A zealous layman and doctor, prominent in Constantinople, later bishop of Doryleum. He publicly opposed Nestorius during the Christmas sermon of 428 and affixed a public accusation against him, charging him with the same heresy as Paul of Samosata. Having been condemned along with Nestorius, he, already bishop of Doryleum and a friend of Eutyches, did not hesitate to present a formal accusation against the heresy of Eutyches to Flavian, bishop of Constantinople, on 8 November 448.
During the Latrocinium of Ephesus—Dioscorus obtained that E. be forbidden to appear, despite the protests of Flavian and the papal legates. Eutyches was rehabilitated and Flavian and E. were deposed and imprisoned. E., after having sent to the Pope an appeal by two of his clerics, managed to escape and took refuge in Rome, where he was still present in April 451 (letter of St. Leo the Great to Pulcheria, Epist., LXXIX, 3; PL 54, 912). When the Council of Chalcedon was opened, he sent to the emperor Marcian and to the Council a statement demanding justice for himself, Flavian, and accusing Dioscorus of heresy. This was followed inevitably by the rehabilitation of E. and the condemnation of Dioscorus. E., however, took part in the approval of canon 28, which established the supremacy of honor of the Church of Constantinople after Rome, despite the refusal of the papal legates. The date of his death is unknown.