The Chalcedonian Fathers explained Canon 28 to Leo as follows:

And we further inform you that we have decided on other things also for the good management and stability of church matters, being persuaded that your holiness will accept and ratify them, when you are told. The long prevailing custom, which the holy Church of God at Constantinople had of ordaining metropolitans for the provinces of Asia, Pontus and Thrace, we have now ratified by the votes of the Synod, not so much by way of conferring a privilege on the See of Constantinople as to provide for the good government of those cities, because of the frequent disorders that arise on the death of their bishops, both clergy and laity being then without a leader and disturbing church order. …

We have ratified also the canon of the 150 holy Fathers who met at Constantinople in the time of the great Theodosius of holy memory, which ordains that after your most holy and Apostolic See, the See of Constantinople shall take precedence, being placed second: for we are persuaded that with your usual care for others you have often extended that Apostolic prestige which belongs to you, to the church in Constantinople also, by virtue of your great disinterestedness in sharing all your own good things with your spiritual kinsfolk. Accordingly vouchsafe most holy and blessed father to accept as your own wish, and as conducing to good government the things which we have resolved on for the removal of all confusion and the confirmation of church order

If this sounds as though the assembled Fathers were nervous about Leo’s reaction, it was because they were. His delegates at Chalcedon had opposed the canon, saying that only the Pope could confer such precedence. The Fathers were, they told Leo, confident that they were acting as he would have wanted. They could not have been more mistaken. Leo’s reaction, a letter to the Emperor Marcian, written on 22 May 452 may be seen in full here. The parts most relevant to our argument are as follows:

Let the city of Constantinople have, as we desire, its high rank, and under the protection of God’s right hand, long enjoy your clemency’s rule. Yet things secular stand on a different basis from things divine: and there can be no sure building save on that rock which the Lord has laid for a foundation.  …….

For the privileges of the churches determined by the canons of the holy Fathers, and fixed by the decrees of the Nicene Synod, cannot be overthrown by any unscrupulous act, nor disturbed by any innovation. And in the faithful execution of this task by the aid of Christ I am bound to display an unflinching devotion; for it is a charge entrusted to me, and it tends to my condemnation if the rules sanctioned by the Fathers and drawn up under the guidance of God’s Spirit at the Synod of Nicæa for the government of the whole Church are violated with my connivance (which God forbid), and if the wishes of a single brother have more weight with me than the common good of the Lord’s whole house.

St. Peter had founded Rome and Antioch, St. Mark, Alexandria; Constantinople owed its foundation to the Emperor, no Apostle had founded it, and any priority it claimed could not be justified on the grounds the other Sees used. Leo’s own representatives, who had not been present when the canon was passed, had protested:

The apostolic see ought not to be humiliated in our presence, and therefore we ask your sublimity to order that whatever was transacted yesterday in our absence in prejudice of the canons or rules be nullified. But if otherwise, let our formal objection be recorded in the minutes, so that we may know what we ought to report to the apostolic man the pope of the universal church, so that he may pass sentence on either the insult to his see or the overturning of the canon. (Price and Gaddis, Acts of Chalcedon, III, p. 91]

Neither tradition, nor apostolic authority sanctioned the novelty that was Canon 28. Its sole basis in ‘tradition’ was canon 8 of Constantinople 381. But this canon was controversial at Rome, and in the form it was recorded at Chalcedon in canon 28 it was also inaccurate, as the Pope’s delegate, Paschasinus pointed out in the sixteenth session. There is a difference between the Greek and Latin versions of the Acta, and since the original is no longer extant, we cannot tell which version is more accurate.

The Latin version asserts Roman primacy, the Greek version omits this. In contemporary terms this did not matter since what was actually at issue was not the relative standing of the two sees but Constantinople’s jurisdiction in the east. It was only later that this difference was elevated to one of importance

But, as we have seen, it did not matter which version was advanced, the one in the canon itself or the conciliatory one put to Leo, he was having none of it because it infringed his unique apostolic privilege. There is no hyperbole, no poetic language – and no chance of misunderstanding. Leo was not having the ancient tradition of the Church usurped by the ambitions of the Imperial city. There was no sure foundation except the rock upon which Christ had built his Church. If ‘Peter speaks through Leo’ meant anything, it meant that Leo spoke with the authority of St Peter himself; not jumped-up Patriarch at Constantinople was going to change that at the best of an Emperor. Christ had spoken, Leo was defending what he had inherited; his successors would do the same.