The See of Peter

The Early Church and Peter's Primacy

Letter I, from Pope Leo to the Bishop of Aquileia

Synopsis: Pelagian clergy have been wrongly admitted to Catholic communion in the bishop’s province without publicly abjuring their error or professing the faith; Leo orders a provincial synod to remedy this, prescribes what they must confess and subscribe, clarifies what must be believed about the grace of Christ, commands the expulsion of any who refuse to comply, and insists that every cleric remain in the church where he was ordained.

Leo, bishop of the Apostolic See, to the Bishop of Aquileia.

I. Pelagian Clergy Have Been Wrongly Received Into Communion Without Recanting Their Error

From the report of our holy brother and fellow bishop Septimus — contained in the letter he attached — we have learned that certain priests, deacons, and clergy of various ranks in your province who were entangled in the Pelagian or Cælestian heresy have been admitted to Catholic communion without any public condemnation of their particular error. While the shepherds charged with vigilance were sleeping too soundly, wolves in sheep’s clothing — as the Gospel warns (Matt. 7:15) — entered the Lord’s fold without leaving behind their predatory minds. They have usurped what canon law denies even to the innocent: abandoning the churches where they received or held their office, they spread their restlessness everywhere, drawn to wander and incapable of remaining on the apostolic foundation. Since they were never examined or bound by any prior profession of faith, they eagerly exploit the appearance of communion to visit many households and — under the cover of a good name — corrupt many hearts that are ignorant of who they really are. This could not have happened if the church’s leaders had applied, when receiving such men, the diligence which the Apostolic See requires — which would have prevented any of them from moving about freely.

II. Leo Orders a Provincial Synod and Prescribes a Formal Profession of Faith

To stop this from continuing, and to prevent the dangerous habit introduced through some people’s negligence from bringing about the ruin of many souls, we decree by our apostolic authority that you, brother, diligently convene a synod of the clergy of your province. All priests, deacons, or clergy of any rank who were rashly received into Catholic communion from the Pelagian or Cælestian sect — without first being required to condemn their error — must now, since their hypocrisy is partly exposed, be brought to genuine correction. This benefits them and harms no one. Let them publicly denounce the authors of this presumptuous error with clear professions, and renounce everything the universal Church has rejected in their doctrine. They must declare, in full and unambiguous written statements signed by their own hand, that they embrace and fully approve all the synodal decrees that the authority of the Apostolic See has confirmed for the eradication of this heresy. Let nothing in their words be obscure or ambiguous — for we know their cunning habit is to preserve whatever part of their execrable doctrine can be kept distinct from the condemned whole.

III. What Must Be Believed and Professed About the Grace of Christ

While they pretend to renounce all their positions in order to deceive, they hold in reserve — unless their intent is exposed — the claim that God’s grace is given in proportion to the recipient’s merits. But if it is not given freely, it is not grace at all, but rather a wage and a repayment for merits, as the blessed Apostle says: By grace you have been saved through faith, and this is not from yourselves, but the gift of God; not from works, lest anyone should boast. For we are his workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them (Eph. 2:8–10). Every bestowal of good works is therefore a divine preparation — for no one is justified by their own effort prior to grace, which is the source of righteousness, the fountain of good, and the origin of merits in all. But these heretics claim that natural effort anticipates grace, so that human nature — distinguished by its own exertion before grace arrives — appears untouched by the wound of original sin, distorting the words of Truth: The Son of Man came to seek and save what was lost (Luke 19:10).

IV. Those Who Refuse the Church’s Decrees on Grace Must Be Expelled

You must be vigilant and take great care, dearest brother, that scandals long extinguished are not revived through such men, and that no seed of this evil — once rooted out — sprouts again in your province to taint the Church’s offspring with its poisonous breath. Those who wish to appear corrected must clear themselves of all suspicion and, by obeying us, prove that they belong to us. If any — whether cleric or layman — refuse to comply with our wholesome decrees, they must be expelled from the society of the Church, lest one who destroys his own soul should also endanger the salvation of others.

V. Each Cleric Must Remain in the Church Where He Was Ordained

We also remind you to restore fully that part of Church discipline — often decreed by the holy Fathers and by ourselves — under which no one in the priesthood, diaconate, or any lower clerical rank may freely move from church to church. Each must persevere where he was ordained, not swayed by ambition, greed, or the corrupt persuasion of other people. If anyone — seeking his own interests rather than those of Jesus Christ — fails to return to his own people and his own church, he shall be excluded from both the privilege of his rank and the bond of communion. Do not doubt, beloved, that we will be deeply troubled if — as we trust will not happen — our decrees for upholding the canons and the integrity of the faith are neglected. For the faults of lower orders are above all the responsibility of leaders who are slothful and negligent — men who often allow great pestilence to take hold by hesitating to apply the stringent remedy of the Apostolic See.

Source/Reference

PL 54:593

Notes / Historical Commentary

Letter I is almost certainly one of the earliest surviving letters of Leo’s pontificate, written sometime after his election in September 440 and probably before 444. It is addressed to the unnamed bishop of Aquileia — the major see of northeastern Italy and the ecclesiastical center of the Venetian and Istrian regions — in response to intelligence forwarded by Septimus of Altinum (also the recipient of Letter II, which covers the same ground). The immediate problem is practical and specific: Pelagian clergy in the bishop’s province have been quietly reabsorbed into Catholic communion without being required to formally abjure their heresy.

The Pelagian controversy had been formally concluded — on paper — at the Council of Carthage in 418 and the subsequent condemnations under Pope Zosimus. But in practice, especially in the Latin West, pockets of Pelagian sympathy persisted for decades. The particular danger Leo identifies here is not open Pelagianism but covert Pelagianism: clergy who have accepted readmission to Catholic communion without having properly renounced the key tenets of their heresy, and who are now free to move between churches, spread their views under the cover of apparent orthodoxy.

The letter is significant for the primacy question from its very opening. Leo does not write to advise or recommend; he writes to order. In Chapter II he invokes his “apostolic authority” explicitly — auctoritate apostolica decernimus — as the basis for commanding the bishop to convene a provincial synod. This is not a request that the bishop take it upon himself to address the problem. It is a papal directive that a specific ecclesiastical action be taken, in a specific form, by a specific date. The Bishop of Aquileia is the instrument of implementation; Rome is the authority that commands it.

The closing warning in Chapter V is particularly pointed. Leo tells the bishop that if his decrees are neglected, he will be “deeply troubled” — and then adds the theological principle that underlies the entire letter: the faults of subordinate clergy are ultimately the responsibility of their bishops, and bishops who fail to apply “the stringent remedy of the Apostolic See” bear the weight of whatever damage results. The phrase Apostolicae sedis districtam medicinam — the Apostolic See’s stringent remedy — frames Rome not merely as one voice among many in the governance of the Church, but as the ultimate corrective instrument whose authority the bishop is expected to exercise on Rome’s behalf in his own province.

This is Letter I — the very first of Leo’s surviving correspondence. The understanding of the papacy it expresses is not a mature elaboration developed over twenty years in office. It is present from the beginning, stated without argument or apology, as the assumed framework within which Leo conducts all his business.