IV. Anatolius' attempts to subvert the decisions of Nicæa are futile.
But at the present time let it be enough to make a general proclamation on all points, that if in any synod any one makes any attempt upon or seems to take occasion of wresting an advantage against the provisions of the Nicene canons, he can inflict no discredit upon their inviolable decrees: and it will be easier for the compacts of any conspiracy to be broken through than for the regulations of the aforesaid canons to be in any particular invalidated. For intrigue loses no opportunity of stealing an advantage, and whenever the course of things brings about a general assembly of priests, it is difficult for the greediness of the unscrupulous not to try to gain some unfair point: just as in the Synod of Ephesus which overthrew the blasphemous Nestorius with his dogma, bishop Juvenal believed that he was capable of holding the presidency of the province of Palestine, and ventured to rally the insubordinate by a lying letter. At which Cyril of blessed memory, bishop of Alexandria, being properly dismayed, pointed out in his letter to me to what audacity the other's cupidity had led him: and with anxious entreaty begged me hard that no assent should be given his unlawful attempts. For be it known to you that we found the original document of Cyril's letter which was sought for in our book-case, and of which you sent us copies. On this, however, my judgment lays special stress that, although a majority of priests through the wiliness of some came to a decision which is found opposed to those constitutions of the 318 fathers, it must be considered void on principles of justice: since the peace of the whole Church cannot otherwise be preserved, except due respect be invariably shown to the canons.
Source: Letters (New Advent)