ACACIUS, bishop of MELITENE. — A good reader, he appears as a reader at Melitene around 390. By the year 431 he is already bishop of that city and as such attends the Ecumenical Council of Ephesus. Relying on his personal relations with Nestorius, he first attempted, though unsuccessfully, to obtain Nestorius’ repentance; then he became a fiery anti-Nestorian.
At the 1st session of the council (22 June 431) he declared his vote in favour of St Cyril’s second letter to Nestorius and at the same time censured Nestorius for his letter against Cyril. When, later, at the 4th session, John of Antioch was summoned to answer for the condemnation he had pronounced against Cyril, A. pointed out the 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 were trying to make passible the divinity in Christ. The attempt was unfounded, as is also evident from the homily delivered by A. at the Council (PG 77, 1467-72). His attendance at the consecration of Nestorius’ successor, Maximian, earned him from John of Antioch a sentence of deposition from his see. His anti-Nestorianism grew stronger still, even to the point of criticizing the reconciliation 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 staunch ally. They alarmed the Armenian bishops. A. died before 449.