Letter CXLVII was written on July 11, 457 — the same day as Letters CXLV and CXLVI — and is addressed to Julian of Cos and the presbyter Aetius, who together served as Pope Leo’s permanent representatives (apocrisiarii) at the imperial court in Constantinople. Julian had served as a papal legate at the Council of Chalcedon in 451 and was among Leo’s most trusted instruments in the East. Where Letter CXLV presented the universal Church’s supplication directly to Emperor Leo I, and Letter CXLVI directed Anatolius of Constantinople to reinforce that supplication from his own proximity to the court, this letter activates Leo’s own men already embedded in the imperial entourage. The three letters constitute a single coordinated campaign, radiating from Rome through multiple simultaneous instruments on the same day.

The structure of the campaign is itself evidence of the Roman pontiff’s ordinary and immediate jurisdiction in operation. Leo does not write to the emperor and await developments; he simultaneously sets in motion every available channel of influence at the eastern court — the patriarch of Constantinople, and his own permanent representatives. None of these instruments acts independently; all are activated by Leo’s letters, directed toward the same objectives, and expected to report back to Rome on the progress of the emperor’s disposition. Anatolius is exhorted; Julian and Aetius are admonished; the emperor is supplicated. The initiative, the direction, and the coordination all flow from a single source.

The closing directive of Chapter II contains the letter’s most jurisdictionally significant phrase: that the bishop appointed for Alexandria must be one to whom “communion with the Apostolic See may be granted.” This is an act of immediate jurisdiction over Alexandria’s episcopal succession, exercised at a distance of thousands of miles through a directive to Leo’s court agents. The grant of communion with the Apostolic See is not a formality or a courtesy — it is the constitutive act that establishes the new bishop’s valid orthodox standing. Leo is specifying not only the criteria of qualification (integrity of conduct and faith, as in Letter CXLV) but the condition of legitimacy itself: communion with Rome. A bishop of Alexandria who does not hold that communion does not hold the position in the full sense that matters. This is the immediate jurisdiction of the Roman pontiff expressed in its most concentrated form: the power to determine, by the grant or withholding of communion, who stands in right relationship to the universal Church.

The reader should note what this formula implicitly rejects. Canon 28 of Chalcedon had attempted to elevate Constantinople to a position of honor second only to Rome and to extend its jurisdictional reach over the eastern dioceses. Leo had formally rejected Canon 28 and continued to do so. The directive here — that Alexandria’s new bishop must receive communion from the Apostolic See — reasserts on its own positive terms what the rejection of Canon 28 asserted negatively: the Roman See is the standard and source of orthodox communion throughout the Church, not one node in a network of equal patriarchal jurisdictions. It does not need Canon 28 to be relitigated here; it only needs to state what the condition of valid episcopal standing at Alexandria is, and that statement carries the full weight of the claim.

Letter CXLVII is brief, but it is one of the more revealing documents in the 457 cluster precisely because of its audience. Leo is not writing to the emperor or to a patriarch; he is writing to his own agents with operational instructions. The tone is that of an administrator directing his staff: rebuke the silence, press the emperor, press the Chalcedonian case, secure the appointment conditions. The rebuking of Julian and Aetius for their silence is itself a small indicator of the relationship: Leo’s permanent representatives at the imperial court are accountable to him for the frequency and usefulness of their reports. The eastern court is not a foreign environment that Leo approaches through formal diplomatic channels; it is a field of operation in which his own men are stationed, and he expects them to function accordingly.