What Is The Tome of Leo?

The Tome of Leo is a letter written in AD 449 by Pope St. Leo to St. Flavian, who was Bishop of Constantinople. Why was this letter sent? After the Council of Ephesus, there arose a new heresy spewed by a monk named Eutyches who taught that after the incarnation, Christ only had one nature, and not two natures (divine and human). Eutyches was condemned by the Bishop, but another "council" was held in defense of Eutyches' teaching and condemned Bishop St. Flavian. This council became known as the Robber Council, which is an invalid council. So, St. Flavian appealed to his brother bishop Pope St. Leo and the letter is the reply. You can read it here. 

The letter is significant for a few reasons. First, it is significant because it is a defense of orthodox teaching on the two natures of Christ. It was so profound, that this letter was appealed to in the next Ecumenical Council, the Council of Chalcedon, which did finally and authoritatively lay to rest the teaching of Eutyches, which we now know as the Monophysite heresy (mono meaning one, physis meaning nature). So the letter, or The Tome of Leo, is a standard of orthodox teaching. As a matter of the history of orthodox Christology, this letter is a classic.

Second, it is significant because of what Pope St. Leo presumes he has the authority to do. He writes at the end, 

Now for the loyal and faithful execution of the whole matter, we have appointed to represent us our brothers Julius Bishop and Renatus priest [of the Title of S. Clement], as well as my son Hilary , deacon. And with them we have associated Dulcitius our notary, whose faith is well approved...

What Pope St. Leo presumes he has the authority to do is set out the terms for the restoration of the heretic Eutyches and send delegates and notaries to ensure the matter is carried out. How is this possible if the jurisdiction of the bishop of Rome is limited to Rome? How is it possible that the Bishop of Rome can instruct and command another Bishop, and the Bishop of Constantinople no less? Pope St. Leo is presuming that his jurisdiction extends that far. And this cannot be possible if Pope St. Leo wasn't absolutely sure of the truth of his own teaching. The two are inseparable. 

And indeed, Pope St. Leo was convinced of the orthodoxy of his teaching, and its binding power upon the rest of the church. In response to the invitation to the Council of Chalcedon, Pope St. Leo writes to the Emperor Theodoius II, 

The devout faith of our most clement prince, knowing that it especially concerns his glory to prevent any seed of error from springing up within the Catholic Church, has paid such deference to the Divine institutions as to apply to the authority of the Apostolic See for a proper settlement: as if he wished it to be declared by the most blessed Peter himself what was praised in his confession...

Pope St. Leo here acknowledges that he is being appealed to in order to properly settle the matter. And he draws his authority to settle the matter by being the successor to St. Peter. In the next few sentences, Pope St. Leo refers to St. Peter's confession in Matthew 16 and then takes the first person pronoun that St. Peter uses and uses it for himself in order to declare Eutyches a heretic and that to deny what he, the Pope, says is equivalent to denying the confession of St. Peter in Matthew 16. So Pope St. Leo is putting his statement on the same divinely revealed level as was given to St. Peter. There is no ambiguity as to how Pope St. Leo understood what he was doing. 

In the same letter to the Emperor, he refers back to his Tome. He writes, 

On receiving our brother and fellow bishop Flavian's letter, we have replied to him at some length on the points which he seems to have referred to us : that when this error which seems to have arisen, has been destroyed, there may be one Faith and one and the same confession throughout the whole world to the praise and glory of God...

Pope St. Leo understood his teaching to be orthodoxy and lay down the foundation for a unitary creed upon the whole world. This is an implausible claim to be making if his jurisdiction is limited only to Rome.  In another letter to the Emperor, he makes this more explicit. He tells the Emperor, 

But what the Catholic Church universally believes and teaches on the mystery of the Lord's Incarnation is contained more fully in the letter which I have sent to my brother and fellow bishop Flavian.

The faith of the church is contained in the Tome of Leo. Again, there does not seem to be much ambiguity afforded here.

What is also of great importance is how others understood the Tome. Sure, maybe Pope St. Leo thought he had all this juridical depth and breadth, but perhaps he was mistaken and was corrected by his brother bishops. This is implausible. 

In the first session of the Council of Chalcedon, which you can read here, shows that everyone seemed to accept the Tome without much reservation (more on those who did have reservations later). You will remember that Bishop St. Flavian was condemned at the Robber Council. So the Council of Chalcedon sought to set the record straight on that matter. When the council was asked whether they thought St. Flavian had erred, this is what was is recorded to have been said by the Bishop of Antioch,

Maximus the most reverend bishop of Antioch in Syria, said: Archbishop Flavian of blessed memory has set forth the faith orthodoxly and in accordance with the most beloved-of-God and most holy Archbishop Leo. And this we all receive with zeal.

In the same response to the question, you had two representatives of Pope Leo say that Flavian is not in error because he agreed with Pope Leo. We cannot consider this by itself very strong evidence that the other Bishops considered Pope Leo to having wider jurisdiction, but the lack of contention to the reasoning does suggest it. It is something to add to the pile of considerations, and they do pile up. 

Another such consideration is what the representatives of Rome say about Jurisdiction. Pope St. Leo did not want Dioscorus who was the Bishop of Alexandria to have a seat as judge at the Council of Chalcedon. Why? 

For he [Dioscorus] undertook to give sentence against one over whom he had no jurisdiction. And he dared to hold a synod without the authority of the Apostolic See [Rome], a thing which had never taken place nor can take place.

So the Bishop of Alexandria cannot pronounce judgment over anyone in Constantinople because he has no jurisdiction there, but you will remember in the Tome that Pope St. Leo does presume he has the authority to proclaim judgment over those in Constantinople. This makes sense if the Bishop of Rome has the authority we Catholics say he does. This is harder for the Orthodox who say the Bishop of Rome's jurisdiction is limited. Further, note that the Pope's representatives also claim that no council can take place without the authority of the Roman Bishop. Again, this is what we expect to see if the Catholic claim that what makes a council valid is ratification of the Roman Bishop is true (I posted a link earlier arguing for this). And again, no one seems to contest this, and the Bishop of Alexandria was not given a seat of judgement. The Bishop of Alexandria (and many others) does say that he deserves punishment for unjustly condemning St. Flavius. 

Consider also how the Council of Chalcedon received the Tome when it was read aloud to them. Here is what the unified bishops shouted, 

This is the faith of the fathers, this is the faith of the Apostles. So we all believe, thus the orthodox believe. Anathema to him who does not thus believe. Peter has spoken thus through Leo. So taught the Apostles. Piously and truly did Leo teach, so taught Cyril. Everlasting be the memory of Cyril. Leo and Cyril taught the same thing, anathema to him who does not so believe. This is the true faith. Those of us who are orthodox thus believe. This is the faith of the fathers. Why were not these things read at Ephesus [i.e. at the heretical synod held there]? These are the things Dioscorus hid away.

The Bishops attributed the speaking of Peter through Leo. In none of the other diocese do we read something like, "Mark as spoken through Dioscorus!" Mark is said to have founded the diocese of Alexandria of which Dioscorus was presently the Bishop of, so why not pull that kind of weight? It seems like the appeal to Peter has a special weight that the other Apostolic diocese do not have. But what is that if not a kind of supremacy?  

The Bishop of Sebastopol declares about the matter,

The matters concerning Eutyches have been examined, and the most holy archbishop of Rome has given a form which we follow and to his letter we all [i.e. those in his neighbourhood] have subscribed.

Okay, sure, but that's just one bishop. That's not sufficient, right? It would be insufficient had the rest of the bishops not cried out in response, 

These [Cyril and Leo's] are the opinions of all of us. The expositions already made are quite sufficient: it is not lawful to make any other. 

It may be objected that the letter of St. Cyril was read to the Council of Chalcedon and was received in a similarly warm manner, but us Catholics don't claim St. Cyril has a supremacy, so we are being inconsistent. Let's look at how the bishops reacted. 

We all so believe: Pope Leo thus believes: anathema to him who divides and to him who confounds: this is the faith of Archbishop Leo: Leo thus believes: Leo and Anatolius so believe: we all thus believe. As Cyril so believe we, all of us: eternal be the memory of Cyril: as the epistles of Cyril teach such is our mind, such has been our faith: such is our faith: this is the mind of Archbishop Leo, so he believes, so he has written.

It is true that language like, "So Cyril taught, so we also believe" is similar to the reaction that was given for Pope St. Leo. It is interesting to note the differences as well. While it was declared that was St. Cyril taught at the previous council is orthodoxy, they were attributing that same infallible orthodoxy to a contemporary, Pope St. Leo. They're saying "This is orthodoxy, which is why Pope Leo believes, and which is why we believe." So we why the bishops believe what they do? Because Pope Leo believes it. And why does Pope Leo believe it? Because it's true. Pope St. Leo then has a special connection to the truth, which the rest of the bishops will definitely have...if only they are in agreement with Pope Leo. Again, how this any different than what Catholics have historically claimed about the Papacy? 

It may also be objected that since the Council of Chalcedon had to examine the Tome, the Tome is therefore not equal to the authority of the Council. But this proves too much, as previous councils had to decide on the canon of scripture, but no one really believes that the Council is therefore superior to the Scriptures or that the Scriptures are subservient to the Councils. 

So, the entire Council of Chalcedon relied on the Tome and the Tome presumes authority. This is Catholicism.