II. Nothing can cancel or modify the Nicene canons.
And so after the not irreproachable beginning of your ordination, after the consecration of the bishop of Antioch, which you claimed for yourself contrary to the regulations of the canons, I grieve, beloved, that you have fallen into this too, that you should try to break down the most sacred constitutions of the Nicene canons: as if this opportunity had expressly offered itself to you for the See of Alexandria to lose its privilege of second place, and the church of Antioch to forego its right to being third in dignity, in order that when these places had been subjected to your jurisdiction, all metropolitan bishops might be deprived of their proper honour.
By which unheard of and never before attempted excesses you went so far beyond yourself as to drag into an occasion of self-seeking, and force connivance from that holy Synod which the zeal of our most Christian prince had convened, solely to extinguish heresy and to confirm the Catholic Faith: as if the unlawful wishes of a multitude could not be rejected, and that state of things which was truly ordained by the Holy Spirit in the canon of Nicæa could in any part be overruled by any one.
Let no synodal councils flatter themselves upon the size of their assemblies, and let not any number of priests, however much larger, dare either to compare or to prefer themselves to those 318 bishops, seeing that the Synod of Nicæa is hallowed by God with such privilege, that whether by fewer or by more ecclesiastical judgments are supported, whatever is opposed to their authority is utterly destitute of all authority.
Source: Letters (New Advent)