in Armenia Secunda, was a firm friend of Cyril of Alexandria, and in 431 published a writing against Nestorius and in defence of the twelve anathemas of Cyril. He was, however, friendly to Nestorius, and strove, before the first session of the Council of Ephesus, to convince him of his errors. The Homily which he delivered before the councils still extant, and acquits him of the charge, brought against him by Alexander of Hierapolis in his letter to Acaciius of Beroea, of maintaining that the Deity was passable. In 457 he united himself with Rabbulas, bishop of Edessa, in an endeavor to hinder the circulation of the words of Theodore of Mopsuestia and Diodorus of Tarsus. The two bishops wrote a joint letter to the bishops of Armenia warning them not to receive the books of Theodore. Acacius also addressed a letter to Cyril congratulating him on the fact of the tribune Aristolaus having received orders (A.D. 432) to enforce peace and to compel every bishop to anathematize the dogmas of Nestorius and Theodore. In this letter he states that he considers it to be an error on the part of those who deny that there, are two sons to say, nevertheless, that he had two natures after the union; and, further, that he considers the opinion that each nature possesses the operations proper to it, so that while one nature suffered the other remained impassible, to be tantamount to an opinion that there are two Sons. In the Greek Church he is reckoned among the saints, and his memory is celebrated on April 17. His extant works are, A Homily, delivered in the Synod of Ephesus, in the collections of councils: Epistle to St. Cyril, in the Epistoloe Ephesince (ed. bv Lupus). See Cave, Hist. Lit. V, 1, 417.