The Roman Faith

Leo the Great held the faith of Rome — the see of Peter and Paul — to be the touchstone of orthodoxy, and his Tome presented itself not as a private theology but as “the faith of Peter” speaking through his successor. This file examines what Leo meant by the “Roman faith”: the Latin theological synthesis he inherited and carried into a conciliar definition (Tertullian, Hilary, Ambrose, Augustine); the East’s enthusiastic reception of his Christology at Chalcedon — “Peter has spoken through Leo” — set carefully against its later non-reception of the papal primacy claims Leo attached to that same authority. The aim, governed by Methodology §4, is to hold apart the shared dogma and the contested ecclesiology — the one confessed by the Church, the other examined by her and not received.

Tradition: Pan-Orthodox (Church Father / Latin)

What Leo Meant by the Roman Faith

For Leo, “the Roman faith” was not a local or partisan creed but the catholic faith held in its purity by the apostolic see of Rome. The conviction has two layers that must be distinguished from the outset, because the later history of East and West turns on telling them apart. The first is doctrinal: Leo believed that the Roman church guarded the apostolic confession intact, and that to test a teaching against the faith of Rome was to test it against the faith of Peter himself. The second is ecclesiological: Leo held that this guardianship was bound up with a unique authority of the Roman see over the universal Church, a primacy of jurisdiction and not merely of honour. In Leo’s own mind the two were a single thing; the subsequent parting of East and West consists precisely in the East receiving the first while declining the second (cf. Wessel, Leo the Great and the Spiritual Rebuilding of a Universal Rome, 285–321; Meyendorff, Imperial Unity and Christian Divisions, 148–155).

When Leo sent the Tome to Flavian, he did not offer it as one bishop’s opinion submitted for debate but as the rule of faith confessed at Rome and therefore binding (Ep. 28.1, 5; trans. Feltoe, NPNF 2nd ser. 12). He expected it to be received, not weighed. This is the “Roman faith” in action: the assumption that the see of Peter speaks the apostolic confession with an authority the rest of the Church is to acknowledge.

The Latin Synthesis Leo Carried

The “Roman faith” Leo confessed was, in its theological substance, the mature deposit of the Latin Christological tradition, and one of Leo’s permanent achievements was to gather that tradition into a single luminous formula and carry it into an Ecumenical Council. His idiom — natura, persona, substantia, forma — is the inheritance of the Western Fathers rather than of the Alexandrian school.

Behind Leo stands Tertullian, who first fixed for the Latin Church the formula of “one person in two substances” (una persona, duae substantiae) and bequeathed the vocabulary of persona and substantia that Leo’s grammar continues (Tertullian, Adversus Praxean 27; cf. Grillmeier, Christ in Christian Tradition, vol. 1, 528–529). Behind him stand Hilary of Poitiers, whose De Trinitate developed the Latin two-natures Christology, and Ambrose of Milan, whose Christological preaching Leo had absorbed. And above all stands Augustine, whose teaching on the one Person of Christ and the integrity of the assumed humanity supplies the deep structure of Leo’s confession (Augustine, Enchiridion 35–40; cf. Wessel, 222–238). The Tome is thus not an ad hoc composition but the precipitate of three centuries of Western reflection. What Leo did was to distill this inheritance into a short, pastoral, quotable letter — and then, crucially, to project it onto the universal stage, so that a local Latin synthesis became, through conciliar reception, a confession of the whole Church (see The Tome to Flavian for the doctrinal exposition).

“Peter Has Spoken Through Leo”: The East Receives the Christology

At the Council of Chalcedon (451), after the Tome was read into the acts, the assembled bishops acclaimed it in words that have echoed ever since: “This is the faith of the Fathers; this is the faith of the Apostles… Peter has spoken through Leo” (ACO II.1.2; Price and Gaddis, The Acts of the Council of Chalcedon, vol. 2, 24–25). The acclamation is the high-water mark of the Eastern reception of the Roman faith. The Greek bishops recognized in Leo’s Latin letter the same Christ they confessed; they declared that “Leo and Cyril teach alike,” and the Chalcedonian Definition is in part the Tome’s precipitate.

Two qualifications keep this reception honest. First, the acclamation was not unconditional: before ratifying the Tome the council appointed a committee to test it against the letters of Cyril, and only when that scrutiny was satisfied did the unreserved praise follow (ACO II.1.2; Price and Gaddis, vol. 2, 9–25). The East received Leo’s Christology because it was found to agree with Cyril, not on the bare authority of Rome. Second, the phrase “Peter has spoken through Leo” is itself read in two ways. To the Roman interpretation it confesses the unique teaching authority of Peter’s successor, vindicated by the council’s submission to his letter. To the Eastern interpretation it praises the content of the Tome as faithful to the apostolic and Petrine confession — Peter spoke through Leo because Leo spoke the faith of Peter, an acclamation of orthodoxy rather than a grant of jurisdiction (cf. Meyendorff, Imperial Unity and Christian Divisions, 165–180; Neil, Leo the Great, 1–28). The same six words thus carry the whole later disagreement in compressed form.

The Petrine Authority Leo Attached

Leo’s understanding of his own office was the most fully developed papal theology the Church had yet seen, and it is inseparable from his sense of the Roman faith. Building on Matthew 16:18–19, Leo taught that Christ founded the Church on Peter, that Peter received a primacy over the other apostles, and that this primacy is perpetuated in the bishops of Rome, who are Peter’s heirs (heres Petri) and act with his authority. Leo expresses this through the Roman-legal category of vicarius: the pope is the unworthy heir through whom Peter himself continues to govern and to speak (Sermon 3 [on the anniversary of his elevation]; Sermon 4; CCSL 138; trans. Freeland & Conway, FOTC 93; cf. Wessel, 285–321; Ullmann, Gelasius I, on the theory’s development). For Leo, then, the Roman faith and the Roman primacy are one fabric: Rome guards the apostolic confession because Peter still presides there. This is the ecclesiology developed in this collection at The Petrine Theology.

Reception of the Dogma, Non-Reception of the Primacy

Here lies the load-bearing distinction this file must hold, in accordance with Methodology §4: the East received Leo’s Christology as pan-Orthodox dogma while declining the ecclesiological claims Leo attached to it. The two cannot be collapsed.

On the dogma, there is no dispute: Leo’s two-natures confession, vindicated at Chalcedon, is shared and binding Orthodox teaching, and Leo is venerated as a saint and Father across the Chalcedonian world. The Eastern Orthodox Church keeps his memory and reads his Tome as a standard of the faith. On this the East and the Catholic West are wholly agreed.

On the primacy, the East drew a different line — and drew it almost at once, at the very council that had praised Leo. Chalcedon’s Canon 28 granted Constantinople, as the New Rome, privileges “equal” to those of Old Rome, grounding Rome’s own pre-eminence in its political status as the imperial city rather than in any unique Petrine commission. Leo protested vehemently and refused to confirm the canon (Ep. 104; Ep. 105; Ep. 106; trans. Feltoe, NPNF 2nd ser. 12). The East, however, retained the canon. The clash is exact and revealing: the same council that acclaimed Leo’s faith enacted an ecclesiology incompatible with his theory of primacy, honouring Rome’s precedence while denying that it rested on the basis Leo claimed (see Leo and Canon 28). The later Orthodox tradition consolidated this into a settled position: Rome’s primacy is a primacy of honour among equal sees, not a primacy of jurisdiction over the universal Church, and the Petrine prerogatives Leo claimed are received as a Roman theologoumenon rather than as catholic dogma (cf. Meyendorff, Imperial Unity and Christian Divisions, 148–180; and the contested-legacy treatment in this collection’s section 09).

[Disputed: whether the Chalcedonian acclamation “Peter has spoken through Leo” and the council’s deference to the Tome constitute a recognition of Roman jurisdictional primacy (the Catholic reading) or only an endorsement of the Tome’s orthodox content (the Orthodox reading) is precisely the contested question between the communions; the same acts are cited by both sides (cf. Price and Gaddis, vol. 2; Meyendorff, Imperial Unity and Christian Divisions, 165–180).]

A Shared Dogma and a Parting Ecclesiology

The net result is a careful asymmetry that the Orthodox tradition has held with consistency. Leo the Great is a Father of the undivided Church, his Christology a permanent possession of Orthodoxy, his Tome a charter of the faith confessed at an Ecumenical Council. In this he is fully received. But the “Roman faith” as Leo himself understood it bound that orthodox Christology to a doctrine of universal papal jurisdiction, and it is this second element — the ecclesiology, not the Christology — that the East did not receive and that became, over the centuries, one of the deep roots of the eventual schism between East and West. To honour Leo as Orthodoxy does is therefore to make a distinction Leo himself did not make: to keep the dogma he taught while setting aside the primacy he claimed. The faith of Peter, on the Eastern reading, is the confession Leo spoke, not the office he held.

References

Leo the Great, Tome to Flavian (Ep. 28), PL 54:755–782; Ep. 104, 105, 106 (on Canon 28); trans. Charles Lett Feltoe, Letters and Sermons of Leo the Great, NPNF 2nd ser. vol. 12 (1895).
Leo the Great, Sermons 3 and 4 (on the anniversary of his elevation), CCSL 138, ed. Antoine Chavasse (Turnhout: Brepols, 1973); PL 54; trans. Jane Patricia Freeland & Agnes Josephine Conway, St. Leo the Great: Sermons, Fathers of the Church 93 (Washington, DC: CUA Press, 1996).
Acts of the Council of Chalcedon (ACO II.1.2); trans. Richard Price and Michael Gaddis, The Acts of the Council of Chalcedon, 3 vols. (Liverpool: Liverpool University Press, 2005).
Tertullian, Adversus Praxean 27.
Augustine, Enchiridion 35–40.
Matthew 16:18–19 (Scripture).
Susan Wessel, Leo the Great and the Spiritual Rebuilding of a Universal Rome (Leiden: Brill, 2008).
Bronwen Neil, Leo the Great, The Early Church Fathers (London: Routledge, 2009).
John Meyendorff, Imperial Unity and Christian Divisions: The Church 450–680 A.D. (Crestwood, NY: SVS Press, 1989).
Aloys Grillmeier, Christ in Christian Tradition, vol. 1, 2nd rev. ed. (London: Mowbray, 1975).