Proterius, bishop of Alexandria, to the most holy and most blessed Pope Leo, bishop of Rome, most dilectissimus fellow priest and fellow bishop, greetings in the Lord.
Chapter I: Proterius Reports That He Has Investigated Leo’s Paschal Inquiry With Diligence, Drawing on the Theophilean Laterculo
The most pious and most faithful emperor Marcian has made known to us through his letters that it is now customary among you to use these Alexandrian computations for Paschal matters — something which your holiness has rightly esteemed. For it would not be fitting for the one whose solicitude for the universal Church rightly inquires into all things to be left uninformed about the manner of calculating the feast, particularly since it pertains to his pastoral duty that God’s worship suffer no error in any part of the world.
I therefore received your holiness’s commonitorium and, reading the letter of your sanctity, I set about diligently investigating this matter in the books of the ancients and in the Laterculo of the most blessed Theophilus, our predecessor, going through them carefully. I have found that in that hundred-year course of the Paschal feast described by the most blessed father and fellow bishop of ours Theophilus — from the first consulship of august Theodosius the elder — the seventy-sixth year’s annotation assigns the Dominical Pascha to the eighth day before the Kalends of May, which is the twenty-fourth day of April.
Chapter II: The Paschal Limits Explained; the Seventy-Sixth Year’s Date Defended Against the Charge of Excess
Lest we appear to be writing or wishing to assert absolute opinions about matters we consider self-evident, we insert here the arguments for this position — so that your sanctity may judge whether the truth of the Alexandrian Church’s computation ought perhaps to be found fault with. It is certain that the solemnity of the Paschal feast, by the labor of many, has been diligently explored and that the Paschal calculation was entrusted, as it is said, to the Alexandrian bishop — since the Egyptians seem, from ancient expertise, to surpass all others in this science. For the Lord himself signified the Paschal solemnity through Moses, saying: Keep in mind the month of new things (Deut. 16:1); and again he said through Scripture: This month shall be for you the beginning of months (Exod. 12:2); and: The Pascha of the Lord, in the fourteenth day of the first month (Lev. 23:5; Num. 28:16). The holy Fathers, considering that this calculation would inevitably cause ambiguity when left to individual discretion, sought to establish a fixed rule from which no deviation would be permitted.
The Sunday Pascha is thus fixed within certain limits: it cannot fall before the eleventh day before the Kalends of April, nor later than the eighth day before the Kalends of May. The span from the eleventh before the Kalends of April to the eighth before the Kalends of May encompasses forty-five days, within which the Dominical Pascha must be sought. Within this span, the Lord himself, when he ate the Pascha with his disciples before his Passion, had the fourteenth lunar day of the first month at his table — and the day following, the fifteenth, he was crucified: which is the sixth feria. And the seventeenth, the first day of the week, he rose from the dead. It is therefore necessary that the Paschal feast — if it is to be celebrated on Sunday — always fall between the fifteenth lunar day of the first month at the earliest and the twenty-first at the latest, so that neither the fast of the preparation be celebrated on the fourteenth day together with the Jews, nor the feast itself be celebrated later than the twenty-first.
Chapter III: The Seventy-Sixth Year of the Laterculo Falls in the Ninety-Third Year from Diocletian; Its Date Is Defended
And so, in the future Paschal solemnity by the eighth Indiction, the twenty-third day of the Pharmuthi, which is the fifteenth Kalends of May, the fourteenth lunar day of the first month falls on the Sunday, at which point in proximity to the preceding form, the conveniently extended twenty-ninth day of the Pharmuthi — which is the ninth Kalends of May — the Dominical Pascha should be celebrated. In the ninety-third year from Diocletian, with the xiv lunar day of the Pharmuthi occurring on Sunday, in proximity to the nearest preceding form conveniently extended, the twenty-ninth of the Pharmuthi — which is the ninth Kalends of May — the Dominical Pascha xxx die mensis Pharmuthi, qui est viii Kalend. Maiar., should be celebrated.
Chapter IV: The Ancient Computation Confirms the Seventy-Sixth Year’s Date; the Fathers Celebrated Pascha in This Way
From the ancient times, even from the beginning, the Lord signified to us through Mosaic law the Paschal mysteries and appointed the most sacred observance — fixing it so that the Pascha of the Lord might be celebrated after the equinox, not before. For the Fathers established that the Paschal celebration must never take place before the vernal equinox — which is the twenty-fifth day of the month of Phamenoth, that is, the twelfth Kalends of April. The reason is that from this equinoctial day, the year of spring commences, and the feast of the Lord’s Resurrection must be celebrated in the season when life renews itself. The holy Fathers also, following the rule of the decemnovennal cycle, never admitted a lunar day from another cycle into computation without careful scrutiny.
Chapter V: The Necessity of the Paschal Celebration by the Eighth Indiction Must Not Cause Anxiety; the Calculation Is Sound
It is necessary therefore that in the coming year of Pascha by the eighth Indiction, the twenty-third day of Pharmuthi — which is the fifteenth Kalends of May, the lunar xiv day occurring on Sunday — the Dominical Pascha be celebrated in proximity to the nearest preceding form conveniently extended, through the twenty-ninth day of the Pharmuthi, which is the ninth Kalends of May. And as our fathers have done and as the sequence of years demands — and as the most ancient writers confirm — the celebration is fixed at that date. The anxiety of temporis imminentis which Theophilus himself had noted in his Prologo Paschali — from which we must carry forward — is resolved by this calculation.
Chapter VI: The Final Determination for the Ninety-Eighth Year of the Laterculo; Confirmation by the Decemnovennal Cycle
Illud etiam necessario vobis innotescimus: quod et in centesimo nonagesimo octavo anno ab imperio Diocletiani, xiv luna rursus occurrente xxiii die mensis Pharmuthi, qui est xiv Kalend. Maiar., Dominicum Pascha xxx die mensis ipsius, qui est vii Kalend. Maiar., Deo praestante celebrabitur. This confirms the pattern: whenever the fourteenth lunar day falls on the twenty-third of Pharmuthi — which is the fifteenth Kalends of May — the Dominical Pascha is celebrated on the twenty-ninth, which is the ninth Kalends of May, this being seven days after the fourteenth lunar day. The rule holds consistently through all cycles.
Chapter VII: Those Who Object That the Feast Recedes to a Second Month Misunderstand the Paschal Limits
Some of those who are subtle in the calculation of the Paschal feast but ignorant of Jewish customs will suppose, if we demand the observance of the feast after the fourteenth lunar day of the first month, that it recedes to a second month. We do not know from where this idea arises. For the fourteenth lunar day of the very first month occurs on the twenty-second of Pharmuthi — which is the fifteenth Kalends of May — so how shall we celebrate Pascha in the second month? For if xiv luna ipsius mensis occurrente xxii die mensis Pharmuthi, qui est xv kal. Maiar., quomodo querelam sustinebimus, quod in secundo mense Pascha celebremus? For the Jews who are ignorant of the Lord and the time of Pascha also celebrate at this time — as has been demonstrated — falling away from the first month once or twice from twelve cycles, and celebrating Pascha in the twelfth month.
Chapter VIII: The Decemnovennal Cycle Is More Reliable Than the Jewish Calculation; the Equinox Establishes the First Month
The most blessed Fathers of ours therefore established the decemnovennal cycle more reliably than the Jewish calculation — because it is impossible to violate the equinox as the foundation and rule, which is the xxv day of the month of Phamenoth, that is, the xii Kalends of April. For it is an error to hold that the equinox begins from the first lunar day of the month starting with the new moon, as some have supposed. All those who rely on the blessed Fathers know well that the annual courses of the decemnovennal cycle carefully annotate the paschales lunas diligently on the fourteenth days. The equinox, which is established at the xxv day of the month Phamenoth, is the xii Kalends of April — and it is certain that the first month’s beginning comes not from a fixed calendar day but from the moment the spring moon arrives after that equinox.
Chapter IX: Proterius Concludes and Entrusts the Final Determination to Leo’s Sanctity
Let those who are in these regions of ambiguity know therefore, through your sanctity, that the legitimate Paschal feast is celebrated on the day which we have explained — not by deviating from the ancient constitution of the Fathers but by following it most exactly. Cognoscant itaque per tuam sanctitatem, qui in illis partibus ambigunt, quod legitime per octavam indictionem Pascha peragemus.
Transferre vero hanc epistolam in Latinae vocis eloquium non satis certum esse putavimus — because for those who speak Greek, it is not possible to render this precisely enough through a less skilled translator, since the cause demanded careful and integral expression. The Graecizing ones who know the matters well, not wishing to offend those who do not know Greek, are willing rather to express it diligently — lest they harm the truth through inexact rendering.
Salute eam quae tecum est fraternitatem. Te quae nobiscum est salutat in Domino. Et alia manu: Valere te, et nostri meminisse, domine, precor, dilectissime et desideratissime frater.
Footnotes
- ↩ Proterius writes to Leo as the bishop charged — per the arrangement Leo had described in Letter CXXI — with reporting the Paschal calculation annually to the Apostolic See. The elaborate honorific address (*sanctissimo ac beatissimo papae Leoni Romanae urbis episcopo*) mirrors the formal language of Anatolius’s Letter CXXXII: the Alexandrian bishop, like the Constantinopolitan patriarch, uses *papa* as the distinctive title of the Roman bishop. The PL apparatus notes that this letter survives in a Latin translation made from a Greek original, the same situation as Letter CXXXII.
- ↩ The emperor is Marcian — who had received Leo’s Letter CXXI asking for an inquiry of Egyptian calculators, and who had transmitted the request to Proterius as Leo had asked. The imperial channel operates here exactly as Leo had designed it: Leo requests the inquiry (CXXI), the emperor transmits it (CXXII directed Julian to press Marcian), and now Proterius reports back to Leo through the same chain.
- ↩ The word *commonitorium* — “letter of instruction” or “directive” — is the same term used throughout Leo’s Illyrian correspondence for the formal written mandate by which the Apostolic See issues binding instructions. Proterius’s use of it for Leo’s Paschal inquiry places the inquiry in the category of an apostolic directive, not merely a collegial consultation.
- ↩ The closing — “and in another hand: May you be well, and may you remember us, lord, I pray, most beloved and most desired brother” — indicates, as with Letter CXXXII, that Proterius added his personal subscription in his own hand to a letter written by scribes. The phrase *domine* — “lord” — is notable in an address to a fellow bishop: it is the language of deference to a superior, not of collegial equality. The PL apparatus places this letter in approximately April 454, as the response to Leo’s inquiry transmitted through Marcian. Leo’s acknowledgment of the reply appears in Letter CXXXVI.
Historical Commentary