ACACIUS, Bishop of Melitene. - A good scholar, he appears as a lector at Melitene around 390. By the year 431 he is already bishop of that city and as such attends the ecumenical Council of Ephesus. Counting on his personal relations with Nestorius, he first attempted to obtain, though in vain, his repentance; then he became a fiery anti-Nestorian.
At the 1st session of the council (22 June 431) he explained his vote in favor of St. Cyril's 2nd letter to Nestorius and at the same time censured the latter for his letter against Cyril. When later, at the 4th session, John of Antioch was cited to appear for the condemnation he had pronounced against Cyril, A. pointed out the complete lack of authority of the Antiochenes. A. was one of the eight legates sent by the Council to Chalcedon to inform Theodosius II, on behalf of the orthodox, of the intrigues of the Antiochenes, who on that occasion accused him of making the divinity in Christ passible. The accusation was unfounded, as also appears from the homily delivered by A. at the Council (PG 77, 1467-72). His assistance at the consecration of Nestorius's successor, Maximian, earned A., at the hands of John of Antioch, deposition from his see. His anti-Nestorianism increased still further, to the point of criticizing the reconciliation that had taken place between Cyril and the Orientals (Synodicon adversus tragoediam Irenaei, chaps. 83 and 213; PG 84, 693-838).
We may ask whether A. did not become tainted with Monophysitism. In his campaign against Theodore of Mopsuestia he found in Rabbula of Edessa a valuable ally. They put the Armenian bishops on their guard. A. died before 449.
Bibliography
Ignazio Ortiz de Urbina