Letter LXXII is addressed personally to Faustus, the presbyter and archimandrite whom Leo had addressed collectively with the other Constantinople archimandrites in Letters XXXII, LI, LXI, and LXXI, and who appears to have been the primary individual correspondent within that community. The letter’s date is uncertain — it exists only in a Greek translation from the Chalcedonian manuscript collection, the Latin original having been lost, which accounts for expressions that are occasionally uncharacteristic of Leo’s style and for the absence of a chronological note. Quesnellus placed it among the letters of 451, but subsequent analysis assigns it to sometime between March and November 450 — before either Theodosius’s death or before news of it reached Rome, on the grounds that the letter’s cautious encouragement presupposes that speaking openly still carries risk.

The letter’s brevity and its coded register are themselves significant. Where Letters LXIX–LXXI had dispatched legates, imposed conditions, and mobilized the full archimandrite network, Letter LXXII is an intimate personal note — warm, encouraging, and theologically pointed in a quiet way. The exhortation not to be ashamed of the Gospel of the generation of the Lord Jesus Christ “according to the flesh” is Leo’s way of sustaining Faustus’s courage without the formal apparatus of a doctrinal letter. In the Constantinople of mid-450, with Chrysaphius still wielding influence and the Eutychian settlement still in place, an archimandrite who held to the two-natures doctrine was under real social and possibly physical pressure. Leo knows this, and his note is calibrated accordingly: the encouragement is pastoral rather than juridical, the doctrinal content is present but embedded, and the closing invitation to write more fully about “matters concerning the common good” keeps the channel open without demanding a formal report.

The transition from this letter to Letter LXXV — which Leo would write to the same Faustus on November 8, 450, after Theodosius’s death — illustrates how rapidly the political situation changed. In Letter LXXII Leo encourages Faustus not to be ashamed of the Gospel in an atmosphere where open defense of the faith still carried risk. In Letter LXXV, written after “the liberty of the Catholics had greatly increased,” the same Faustus can be addressed with full doctrinal confidence. The change is not in Leo’s theological position — it never changed — but in the political environment in which Faustus had to live. Theodosius’s death removed the court pressure that had made discretion necessary, and Letter LXXII is the last letter in the corpus written under its shadow.