This letter, sent by Acacius of Constantinople to Pope Simplicius in late 477 or early 478, reports the resolution of the Alexandrian crisis that had been the principal subject of Simplicius’s correspondence over the preceding two years. Timothy Aelurus, restored to Alexandria by Basiliscus in 475 and the target of Simplicius’s protests in Letters IV through VII, had died on July 31, 477. Peter Mongus, his archdeacon and the leader of the Monophysite party at Alexandria, had attempted to seize the see in the gap between Aelurus’s death and burial but had been driven out and gone into hiding. Timothy Salofaciolus, the Catholic claimant who had been displaced by Aelurus’s restoration, had been brought back to his see. Acacius writes to inform Simplicius of all this, in the deferential register of a fully cooperating Eastern patriarch reporting good news to the bishop of Rome.

The opening sentence is the most significant feature of the letter for the primacy question. Acacius applies to Simplicius the phrase from 2 Corinthians 11:28 by which Paul described his own apostolic burden — sollicitudo omnium ecclesiarum, “the solicitude of all the Churches.” The transfer of the Pauline phrase from Paul to the Roman bishop is exact and deliberate. Acacius is acknowledging that the bishop of Rome bears the apostolic burden of universal pastoral concern — the same burden Paul described, now exercised through the Roman see. This is precisely the formula Leo had used repeatedly to characterize his own office, and that Simplicius had named in Letter IV (“the solicitude of apostolic governance”). The reader should attend to what it means that this acknowledgment comes from Constantinople. It is not Rome claiming what Constantinople disputes; it is Constantinople using Rome’s own self-understanding as the natural framework for addressing the Roman bishop. At the moment Acacius wrote, no boundary between his theological convictions and Rome’s was in evidence, and he uses Roman language as fluently as Rome uses it itself.

The letter’s second significant primacy feature is Acacius’s reference to the documentary record. He says that the events surrounding Peter Mongus are recorded “in our archives, and from your records, if you deign to inquire” — placing Roman archives alongside Constantinopolitan ones as the natural reference point for verifying what happened, and using deference language (si dignamini requirere) for the very act of Roman consultation. The phrase presupposes the administrative reality that Rome held copies of papal correspondence going back generations, and that Eastern parties knew it. The reference to the bishop of Alexandria writing to Rome — and Rome’s records preserving the exchange — treats Rome as the documentary center to which the historical question naturally returns. This is not a controverted claim Acacius is conceding; it is the structural fact he is invoking.

The Davidic comparison applied to Timothy Salofaciolus parallels the same comparison Simplicius had applied to Zeno in Letter VIII. The just man patient under unjust displacement, restored by divine action — the type fits both the emperor restored from his exile under Basiliscus and the Catholic patriarch restored from his displacement under Aelurus. The reader should notice how the same theological pattern is being read across the entire 476–477 cluster of events: Basiliscus’s reversal of Catholic order is read as the time of testing, and the restoration of Catholic figures (Zeno to the throne, Salofaciolus to Alexandria) is read as God’s restoring action. Acacius and Simplicius are reading the same providential narrative; their cooperation in reading it is part of what makes the moment of this letter the high-water mark of Roman–Constantinopolitan unity in this period.

The dramatic irony of the letter — for the reader who knows what comes next — is impossible to miss. Acacius is writing in full theological cooperation with Rome, using Roman language about papal solicitude, treating Rome as the documentary center, employing the same providential reading of events that Simplicius is using. He describes Peter Mongus as having been driven into “eternal flight.” Within five years, the Emperor Zeno would issue the Henoticon (482), formally seeking reconciliation with the Monophysites, and Acacius would be the principal Eastern architect of that reconciliation. Peter Mongus would be installed as the official patriarch of Alexandria under the terms of the Henoticon, with Acacius’s support. The “eternal flight” of this letter would prove to have been a brief one. Within seven years of this letter, Acacius’s successor in Roman estimation would be Felix III, who would excommunicate him in 484. The acknowledgment of papal solicitude with which this letter opens — sincere when written — would become, in the schism that followed, evidence that the bishop of Constantinople had once known and acknowledged what he later acted against.

One observation about the letter’s place in the Acacian arc. The relationship that produced this letter was not a polite formality but a working ecclesiastical alliance. Simplicius and Acacius corresponded throughout the Basiliscus crisis, coordinated their resistance to the Encyclical, supported each other against the imperial pressure, and held the Catholic position together until the moment of restoration. Letter VIII (Simplicius to Zeno) and this letter from Acacius belong to the same moment and to the same shared theological reading of events. What broke the alliance was not theology in the abstract but the political pressure of the Henoticon period: the slow drift, the search for compromise formulas, the willingness to accept reconciliation on terms Rome would not approve. The reader should understand that the schism of 484 did not begin with hostility between Rome and Constantinople. It began with letters like this one — written in cooperation, under shared assumptions, by parties who could not yet foresee what the politics of the next decade would do to their alliance.