There has been some difference of opinion among the learned as to whether St. Cyril's Synodal letter which has at its end the anathemas against Nestorius, which hereafter follow, was formally approved at the Council of Ephesus. The matter is one only of archeological and historical interest for from a theological point of view the question is entirely uninteresting, since there is no possible doubt that the synod endorsed St. Cyril's teaching and for that express reason proceeded at their first session to excommunicate Nestorius. Further there is no one that disputes that the anathematisms were received at the next General Council. i.e., of Chalcedon, only twenty years later, and that Theodoret was condemned by the Fifth Ecumenical Council because he wrote against these very Anathemas. This being the case, to those who value the decrees of Ecumenical Councils because of their ecumenical character, it is quite immaterial whether these anathematisms were received and approved by the third Council or no, provided, which is indisputably the case, they have been approved by some one council of ecumenical authority, so as to become thereby part and parcel of the ecumenical faith of the Church.
But the historical question is one of some interest, and I shall very briefly consider it. We have indeed the "Acta" of this council, but I cannot but agree with the very learned Jesuit Petavius and the Gallican Tillemont in thinking them in a very unsatisfactory condition. I am fully aware of the temerity of making such a suggestion, but I cannot help feeling that in the remarks of the Roman representatives, especially in those of the presbyter-legate, there is some anachronism. Be this as it may, it is a fact that the Acts do not recite that this letter of Cyril's was read, nor do they state that the Anathemas were received. I would suggest, however, that for those who defend John of Antioch, and criticise the action of St. Cyril, it is the height of inconsistency to deny that the Council adopted the Anathemas. If it was the bitterly partisan assembly that they would have us believe, absolutely under the control of Cyril, there is nothing that, a priori, they would have been more sure to do than adopt the Anathemas which were universally looked upon as the very fulcrum on which the whole matter turned.
Bishop Hefele was at first of opinion that the letter was merely read, being led to this conclusion by the silence of the Acts with regard to any acceptance of it, and indeed at first wrote on that side, but he afterwards saw grounds to change his mind and expresses them with his usual clearness, in the following words: (Hefele, Hist. of Councils. Vol. III., p. 48, note 2.)
We were formerly of opinion that these anathematisms were read at Ephesus, but not expressly confirmed, as there is hardly anything on the subject in the Acts. But in the Fifth Ecumenical Council (collatio vj.) it is said: "The holy Council at Chalcedon approved this teaching of Cyril of blessed memory, and received his Synodical letters, to one of which are appended the xij. anathemas" (Mansi, t. ix., p. 341; Hardouin, t. iij., p. 167). If, however, the anathematisms of Cyril were expressly confirmed at Chalcedon, there was even more reason for doing so at Ephesus. And Ibas, in his well-known letter to Maris, says expressly that the Synod of Ephesus confirmed the anathematisms of Cyril, and the same was asserted even by the bishops of Antioch at Ephesus in a letter to the Emperor.
From all these considerations it would seem that Tillemont's(1) conclusion is well rounded that the Synod certainly discussed the anathemas of Cyril in detail, but that here, as in many other places, there are parts of the Acts lacking. I shall add the opinion of Petavius. (Petavius, De Incarnatione, Lib. VI., cap. xvij.)
The Acts do not tell us what judgment the Synod of Ephesus gave with respect to the third letter of Cyril, and with regard to the anathemas attached to it. But the Acts in other respects also have not come down to us in their integrity. That that third letter was received and approved by the Ephesine Council there can be no doubt, and this the Catholics shewed in their dispute with the Acephali in the Collation held at Constantinople under the Emperor Justinian in the year of Christ 811. For at that memorable meeting some-tiring was shewn forth concerning this letter and its anathemas, which has a connexion with the matter in hand, and therefore must not be omitted. At that meeting the Opposers, that is the Acephali, the enemies of the Council of Chalcedon, made this objection against that Council: "The [letter] of the Twelve Anathemas which is inserted in the holy Council of Ephesus, and which you cannot deny to be synodical, why did not Chalcedon receive it?" etc., etc.
From this it is evident that the prevailing opinion, then as now, was that the Twelve Anathemas were defined as part of the faith by the Council of Ephesus. Perhaps I may close this treatment of the subject in the words of Denziger, being the caption he gives the xij. Anathematisms in his Enchiridion, under "Decrees of the Third Ecumenical Council, that of Ephesus." "The Third Synod received these anathematisms; the Fourth Synod placed them in its Acts and styled the Epistles of Cyril `Canonical' ; the Fifth Synod defended them."