Epistola Ad Leonem Papam

To my most beloved lord, brother, and fellow priest Leo, Proterius sends greetings in the Lord. Our most pious and faithful emperor, Marcian, recently made use of a venerable letter addressed to us, in which he asserted that some persons were reckoning that the day of the paschal feast, which, with the Lord’s help, is to be celebrated in the coming eighth indiction, had not been carefully recorded. However, he indicated this not as if moved by his own impulse, but because he had received writings of your holiness. And he commanded that we ought diligently to investigate the matter, employing a most thorough scrutiny, which would require much care and effort. For this reason, it was not to be neglected that I should at once examine the business; especially since from that time when I received the memorandum of your reverence, I have had very great concern for this matter, now consulting the legal books, now examining the institutes of the ancient doctors, from which it is possible to investigate such a computation more skillfully. Also, taking up the centennial cycle of Easter, written by our most blessed father and fellow bishop Theophilus, and running through it entirely, I found it so carefully and completely composed that whoever he may be, he cannot in any way reproach or censure the authority of this writing.

For it was inconsistent that a man so vigilant and most dear to God, also enriched with knowledge of the divine Scriptures, could have erred in so great and necessary a matter, having omitted the labor of diligence. But perhaps, as your holiness writes, it is the fault of a faulty codex or a scribal error; and for that reason we ought to transfer the day of that holy festival, which may it not be. Let it rather be celebrated as the centenary cycle of years of that same most blessed father and fellow bishop Theophilus contains; which entirely agrees with the pages of the ancients, that is, on the day of the month Pharmouthi, according to the Egyptians, which is the eighth of the Kalends of May. And we, and the whole Egyptian region, and the entire East, will celebrate that same day, God willing. But so that we may not be thought to write or wish to affirm absolutely what seems to us, we have also inserted the reasons for this letter, by which your holiness may perhaps judge that it should not reproach the truth of the Egyptian Church, which has been the mother of this kind of labor and has diligently recorded it. Long ago, indeed, the Lord through Moses signified the paschal time, saying: "Keep the month of new [grain]," declaring this to be the first; as he also says: "This month shall be for you the beginning of months; it shall be the first of the months of the year; and you shall keep the Passover to the Lord your God on the fourteenth day of the first month.

But the Lord who spoke these things through Moses, being the fullness of the law, when He deigned to become man, on the fifth day of the week, the fourteenth day of the moon of the first month, in the upper room ate the Passover with His disciples, and shortly after was betrayed by Judas; and on the following day, the fifteenth day of the moon, He was crucified, that is, on the sixth day of the week; and descending into hell, completing the dispensations of our salvation, on the evening of the Sabbath, as the Lord’s Day was dawning, He rose from the dead; on which day the moon of the first month according to the Hebrews is manifestly shown to have existed. We Christians, therefore, seek not only the fourteenth day of the moon at Passover (for the Jews, doing this, are without festivity); but we also more carefully observe the day of the Resurrection of our Redeemer, which is the seventeenth day of the moon of the aforementioned first month of the new [moon]. If the full moon always occurred in the same way on the fifth day of the week, when the Savior ate the Passover with His disciples, all ambiguity would be removed. But because the cycle of the moon is unequal to the course of the sun, and the fourteenth day of the paschal moon often falls on the Lord’s Day, it is not possible then to celebrate the feast; but neither on the day before, the Sabbath, with the thirteenth day of the moon, to break the fast; it must be deferred to the following week; especially since within it we have the fifteenth day of the moon, when, as the Apostle wrote, our Passover, Christ, was sacrificed.

The fourteenth moon of the first month according to the Hebrews, as was said above, Jesus ate the typical Passover; on the following sixth day of the week, the fifteenth moon, He was affixed to the cross for us like a sheep for slaughter; and on the evening of the Sabbath, at the dawning of the Lord's day, the seventeenth moon, He rose from the dead. Therefore, since in the coming Paschal solemnity, in the eighth indiction, on the twenty-second day of the month Pharmouthi of the new fruits, which is the fifteenth day before the Kalends of May, the fourteenth moon falls on the Lord's day, it is fitting to defer to the following week. For having within it the three-day mystery, that is the fifteenth moon, when Christ was crucified, adhering to the fourteenth; and also the sixteenth and the following seventeenth; on the twenty-eighth day of the month Pharmouthi, which is the ninth day before the Kalends of May, we will break the fasts on the evening of the Sabbath. On the following dawning Lord's day, the twenty-ninth day of that same month Pharmouthi, which is the eighth day before the Kalends of May, we will celebrate the feast most sincerely.

For also in former times, if ever the fourteenth moon was found on the Lord's day, the feast was deferred to the following week. As is proven in the eighty-ninth and ninety-third years from the reign of Diocletian. For thus also our most blessed Fathers are declared to have done (in the year of Christ 373). In the eighty-ninth year indeed from the reign of Diocletian, with our Father and bishop Athanasius of blessed memory still living, when the paschal fourteenth moon fell on the twenty-eighth day of the month Phamenoth, that is, the ninth day before the Kalends of April, on the Lord's day, it was transferred to the following week; so that the paschal Lord's day was celebrated on the fifth day of the month Pharmuthi, that is, the day before the Kalends of April. In the ninety-third year from the reign of the same Diocletian, when the paschal fourteenth moon fell on the fourteenth day of the month Pharmuthi, which is the fifth day before the Ides of April, on the Lord's day, a deferral was likewise made to the following week: so that the paschal Lord's day was solemnly observed on the twenty-first day of the month Pharmuthi, which is the sixteenth day before the Kalends of May. Also in the hundred and third year from the reign of the aforementioned Diocletian (in the year of Christ 387), when the paschal fourteenth moon was about to fall on the twenty-third day of Pharmuthi, which is the fourteenth day before the Kalends of May, on the Lord's day; again a week was sought, and the paschal Lord's day is known to have been celebrated on the day of that same month Pharmuthi which is the seventh day before the Kalends of May, on account of the imminent shortness of time.

Likewise, in the one hundred and sixtieth year (Anno Domini 444) from the reign of Diocletian, when the paschal moon fell on the twenty-third day of Pharmouthi, which is the fourteenth day before the Kalends of May, on the third day of the week (Tuesday), and we remember that we celebrated the Lord's Pascha on the twenty-eighth day of the same month of Pharmouthi, which is the ninth day before the Kalends of May. It is therefore necessary, in the two hundred and fifty-fifth year from the reign of Diocletian, at the future paschal feast of the eighth indiction, on the twenty-second day of Pharmouthi, which is the fifteenth day before the Kalends of May, the fourteenth moon falling on the Lord's day (Sunday), that it be fittingly extended to the following week, according to the preceding form, so that we celebrate the Lord's Pascha on the twenty-ninth day of the month of Pharmouthi, which is the eighth day before the Kalends of May, on account of the strait again impending; just as our Fathers did, deferring the fourteenth moons when they fell on the Lord's day. For if we celebrate Pascha on the twenty-second day of the month of Pharmouthi, which is the fifteenth day before the Kalends of May, when the fourteenth moon, as I have said, often falls on the Lord's day, we will find that on the previous day, that is the Sabbath (Saturday), the twenty-first day of the same month, which is the sixteenth day before the Kalends of May, the thirteenth moon then existing, we do not properly break the fast. For the paschal feast is not eaten on the thirteenth moon.

Therefore, because the twenty-second day of the month of Pharmouthi, which is the fifteenth day before the Kalends of May, falls on a Sunday, and the fourteenth moon occurs on that day; and it is not fitting to fast on a Sunday, for this is proper to the Manichaeans: it follows that we should proceed to the following week, within which, as we have said, we have both the fifteenth moon, when the Lord was crucified, and the sixteenth moon, together with the seventeenth moon, when He rose from the dead. Thus, on the twenty-eighth day of the month of Pharmouthi, which is the ninth day before the Kalends of May, in the evening of the Sabbath we shall break the fasts according to custom, and on the following Sunday, the twenty-ninth day of that same month, which is the eighth day before the Kalends of May, we shall celebrate the paschal feast. We also make known to you of necessity, that in the coming year 265 from the reign of Diocletian, the fourteenth moon again occurring on the eighteenth day of the month of Pharmouthi, which is the fourteenth day before the Kalends of May, the Sunday of Easter, on the twenty-eighth day of that same month, which is the seventh day before the Kalends of May, will, with God’s favor, be celebrated.

But some, perhaps ignorant of the subtlety of the paschal computation, deceived by Jewish fables, will think that we are retreating into the second month if we postpone the feast until then—I do not know at all whence they assert this. For when the fourteenth moon of that month occurs on the twenty-second day of the month of Pharmouthi, which is the fifteenth day before the Kalends of May, how shall we endure the complaint that we are celebrating Easter in the second month? For the Jews, ignorant of the Lord, are also ignorant of the time of Easter. Hence they often depart from the first month and think that they are celebrating Easter in the twelfth month to some extent. But our most blessed fathers, more certainly establishing the nineteen-year cycle, which it is impossible to violate, set this nineteen-year computation as a foundation, a base, and a rule: not according to the unlearned and inept actions of the Jews, nor according to the putative and feigned prudence of others, but according to the grace of the Holy Spirit instituted, they more carefully noted the paschal fourteenth moons in the revolution of the oft-mentioned nineteen-year cycle.

Having thus completed these matters, it is also necessary to observe that those who set the beginning of the first lunar month entirely on the 25th day of the month Phamenoth, which is the 12th day before the Kalends of April, are greatly in error, because the beginning of springtime seems to have been fixed with all diligence by those who were able to discover this, and indeed according to the course of the sun, the equinox is clearly known to be on the 25th day of the month Phamenoth, which is the 12th day before the Kalends of April. But it is not necessary to fix the beginning of the first month, according to the course of the moon, precisely from this equinox. Otherwise, the course of the moon would have to agree in all respects with the circle of the sun. But because it is certain to all who have understanding that the very swift motion of the moon is by no means followed by the course of the sun, come now, briefly, with God's help, let us instruct the doubtful that we cannot in any way exceed into the second month. For if the beginning of the month were established at the equinox, that is, on the 25th day of the month Phamenoth, which is the 12th day before the Kalends of April, according to the course of the moon, it would be reasonable for some to think that we could recede into the second month. But now, because the 14th moon of the first month is found, through the eighth indiction, which will come on the 22nd day of the month Pharmothi, which is the 15th day before the Kalends of May, it is certain that the beginning of that same first month, according to the course of the moon, occurs on the 9th day of Pharmothi, which is the day before the Nones of April.

Since therefore the fourteenth moon is found on the 22nd day of the month Pharmothi, which is the 4th day before the Kalends of May, celebrating the Lord's Passover on the 29th day of the same month Pharmothi, which is the 8th day before the Kalends of May, we by no means recede into the second month, since we then undoubtedly have the 21st moon. How then shall we run into the second month, when the beginning of the first month according to the course of the moon, as was said a little before, falls on the 9th day of the month Pharmothi, which is the day before the Nones of April, and the 14th moon occurs on the 22nd day of that same month, that is, the 15th day before the Kalends of May? This having been thus declared, it is certain that we by no means run into the second month, celebrating the Lord's Passover on the 29th day of the month Pharmothi, which is the 8th day before the Kalends of May. Let it therefore be known through your Holiness to those who are in doubt in those parts, that we legitimately celebrate the Passover in the eighth indiction. For this reason indeed I have written, following the Fathers and the ecclesiastical formulas in this matter, and taking from them the occasions for this subject. For thus also our predecessors, whenever doubt arose, hastened to announce beforehand, so that the holy festival might be celebrated uniformly everywhere. Which also now, according to ancient custom, we believe is proclaimed in the churches in the Lord: one faith, one baptism, and one most sacred Paschal solemnity, to be celebrated by all Christians everywhere in Christ Jesus our Lord; because in Him we live, and move, and are.

We thought it not sufficiently certain to translate this letter into the eloquence of the Latin tongue, lest, perhaps, by Grecizing among us, and no longer being able to express these things diligently, we should harm the truth, on account of an unformed and incongruous style, and one which might not be able to be rendered so ardently and knowledgeably as the cause demanded. Greet that brotherhood which is with you. The brotherhood which is with us greets you in the Lord. And in another hand: I pray, most beloved and most desired lord brother, that you be well and remember us.