Leo to Maximus of Antioch.
How much, beloved, you have at heart the most sacred unity of our common Faith and the tranquil harmony of the Church's peace, the substance of your letter shows, which was brought me by our sons, Marian the presbyter and Olympius the deacon, and which was the more welcome to us because thereby we can join as it were in conversation, and thus the grace of God becomes more and more known and greater joy is felt through the whole world over the revelation of catholic Truth. And yet we are sore grieved at some who still (so your messengers indicate) love their darkness; and though the brightness of day has arisen everywhere, even still delight in the obscurity of their blindness, and abandoning the Faith, remain Christians in only the empty name, without knowledge to discern one error from another, and to distinguish the blasphemy of Nestorius from the impiety of Eutyches. For no delusion of theirs can appear excusable, because they contradict themselves in their perverseness. For, though Eutyches' disciples abhor Nestorius, and the followers of Nestorius anathematize Eutyches, yet in the judgment of catholics both sides are condemned and both heresies alike are cut away from the body of the Church: because neither falsehood can be in unison with us. Nor does it matter in which direction of blasphemy they disagree with the truth of the Lord's Incarnation, since their erroneous opinions hold neither with the authority of the Gospel nor with the significance of the mystery(1) .
And therefore, beloved brother, you must with all your heart consider over which church the Lord has set you to preside, and remember that system of doctrine of which the chief of all the Apostles, the blessed Peter, laid the foundation, not only by his uniform preaching throughout the world, but especially by his teaching in the cities of Antioch and Rome: so that you may understand that he demands of him who is set over the home of his own renown those institutions which he handed down, as he received them from the Truth Itself, which he confessed. And in the churches of the East, and especially in those which the canons of the most holy Fathers at Nicaea(2) assigned to the See of Antioch, you must not by any means allow unscrupulous heretics to make assaults on the Gospel, and the dogmas of either Nestorius or Eutyches to be maintained by any one. Since, as I have said, the rock (petra) of the catholic Faith, from which the blessed Apostle Peter took his name at the Lord's hands, rejects every trace of either heresy; for it openly and clearly anathematizes Nestorius for separating the nature of the Word and of the flesh in the blessed Virgin's conception, for dividing the one Christ into two, and for wishing to distinguish between the person of the Godhead and the person of the Manhood: because He is altogether one and the same who in His eternal Deity was born of the Father without time, and in His true flesh was born of His mother in time; and similarly it eschews Eutyches for ignoring the reality of the human flesh in the Lord Jesus Christ, and asserting the transformation of the Word Himself into flesh, so that His birth, nurture, growth, suffering, death and burial, and resurrection on the third day, all belonged to His Deity only, which put on not the reality but the semblance of the form of a slave.
And so it behoves you to use the utmost vigilance, lest these depraved heretics dare to assert themselves; for you must resist them with all the authority of priests, and frequently inform us by your reports what is being done for the progress of the churches. For it is right that you should share this responsibility with the Apostolic See, and realize that the privileges of the third See in Christendom(3) give you every confidence in action, privileges which no intrigues shall in any way impair: because my respect for the Nicene canons is such that I never have allowed nor ever will the institutions of the holy Fathers to be violated by any innovation. For different sometimes as are the deserts of individual prelates, yet the rights of their Sees are permanent: and although rivalry may perchance cause some disturbance about them, yet it cannot impair their dignity. Wherefore, brother, if ever you consider any action ought to be taken to uphold the privileges of the church of Antioch, be sure to explain it in a letter of your own, that we may be able to reply to your application completely and appropriately.
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(4) . At which Cyril of blessed memory, bishop of Alexandria, being properly dismayed, pointed out in his letter to me(5) 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 especial 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.
Of course, if anything is alleged to have been done by those brethren whom I sent in my stead to the holy Synod, beyond that which was germane to the Faith, it shall he of no weight at all: because they were sent by the Apostolic See only for the purpose of extirpating heresy and upholding the catholic Faith. For whatever is laid before bishops for inquiry beyond the particular subjects which come before synodal councils may admit of a certain amount of free discussion, if the holy Fathers have laid down nothing thereon at Nicaea. For anything that is not in agreement with their rules and constitutions can never obtain the assent of the Apostolic See. But how great must be the diligence with which this rule is kept, you will gather from the copies of the letter which we sent to the bishop of Constantinople, restraining his cupidity; and you shall take order that it reach the knowledge of all our brethren and fellow-priests.
This too it behaves you, beloved, to guard against, that no one except those who are the Lord's priests dare to claim the right of teaching or preaching, be he monk or layman(6) , who boasts himself of some knowledge. Because although it is desirable that all the Church's sons should understand the things which are right and sound, yet it is permitted to none outside the priestly rank to assume the office of preacher, since in the Church of God all things ought to be orderly, that in Christ's one body the more excellent members should fulfil their own duties, and the lower not resist the higher. Dated the 11th of June, in the consulship of the illustrious Opilio (453).