Letter CLXI, dated March 21, 458, is the second of the three-letter cluster of that day — alongside Letter CLX to the exiled Egyptian clergy and Letter CLXII to the emperor — and it completes the running disciplinary case of Atticus the presbyter that Leo first opened in Letter CLI seven months earlier. But it does more than close a case; it demonstrates, in the clearest possible way, what the ordinary and immediate jurisdiction of the Roman pontiff means when a subordinate bishop has failed to act.

The letter is addressed not to Anatolius of Constantinople but directly to the clergy of his church. This is the sharpest jurisdictional move in the entire Atticus episode, and its structural significance should not be underestimated. Leo had issued the same directive — investigate, correct or expel — through Anatolius in three successive letters over seven months (CLI, CLV, CLVII). Anatolius did not comply. Leo’s response is not to write a fourth letter to Anatolius; it is to bypass him entirely and address the clergy directly. The immediate jurisdiction of the Roman pontiff is not mediated through the local bishop; it reaches the clergy of another bishop’s church without the bishop as an intermediary. By writing directly to the Constantinople clergy, Leo is not going around Anatolius as a matter of procedural creativity; he is exercising the jurisdiction that his office holds over every church, which does not require the local bishop’s mediation to operate.

The specific requirements Leo imposes on Atticus and Andreas in Chapter II are as precisely juridical as any ruling in this cluster. Two distinct acts are required: an oral public profession of faith before the Christian people assembled in the church, and a written subscription documenting that profession. Neither alone is sufficient. The venue is specified — the church itself, with the congregation present. The content is specified — condemnation of the hostile doctrines and profession of Chalcedonian faith. Leo is prescribing the precise form of the required juridical act, including its public and liturgical character. The form is not arbitrary: Atticus’s offense was public disputation against the faith in the church; the remedy must be a public act of profession in that same setting. The public character of the correction mirrors the public character of the scandal.

Chapter II also contains one of the most precise statements in the corpus of what the irreformability of defined doctrine means in practice. Leo writes that once debate on a settled matter is admitted, authority is eroded — dum disceptatio admittitur, auctoritas auferatur. This is not merely a tactical argument about the Eutychians’ motives. It is a theological principle: the moment you agree to debate what has been defined, you have conceded that the definition is open to revision — and that concession is the settlement’s undoing. Reopening the question is not a preliminary step toward settling it again; it is itself the destruction of the settlement. This principle underlies every refusal in this cluster to entertain the demand for a new council. Leo does not argue against a new council on the merits; he refuses to engage the question at all, because engaging it would already be a concession that the question is open.

The letter also illuminates, in passing, the mechanics of Leo’s cross-referencing across his own correspondence. He tells the Constantinople clergy that he has identified Atticus and Andreas to Anatolius “in letters sent earlier” — a reference to CLI, CLV, and CLVII. Leo is not treating each letter as an isolated communication; he is building a documented record across multiple letters, each of which references and builds on the previous ones. The Atticus case is not resolved in a single intervention; it is prosecuted systematically over months, with each letter adding to the record. The final ruling to the clergy directly is the outcome of that documented process — a process Leo has been conducting in writing, step by step, since September 1, 457.