Patriarch of Constantinople and a disciple of St. John Chrysostom. A native of Constantinople, he studied under St. John and then served as secretary to John’s enemy, Patriarch Atticus of Constantinople. Ordained by Atticus, he was soon named bishop of Cyzicus, although the inhabitants of the diocese refused to have him for their bishop. Known for his eloquent preaching, he became a vocal opponent of the heretical patriarch Nestorius from 428 and the latter’s appointment by Emperor Theodosius II. Six years later, Proclus was himself appointed patriarch of Constantinople, following the death of Patriarch Maximian, who had replaced the deposed Nestorius. As patriarch, he was conspicuous in his opposition to the Nestorian heresy, although he treated the heretics with remarkable patience and forbearance, and gave aid to the people of the city following a terrible earthquake. In 438 he secured the translation of the body of St. John Chrysostom. Proclus’ body of writings, comprised mainly of epistles and homilies, included the Tome of St. Proclus, a treatise on the doctrine of the two natures of Christ which was addressed to the Armenians and was intended to refute the unorthodox teachings of Theodore of Mopsuestia. He is also the attributed composer of the Trisagion of the liturgy.