Constantine's Letter to the Churches Respecting the Council at Nicæa.
Chapters XVII-XX Of Eusebius' Ecclesiastical History
"Constantinus Augustus, to the Churches.
"Having had full proof, in the general prosperity of the empire, how great the favor of God has been towards us, I have judged that it ought to be the first object of my endeavors, that unity of faith, sincerity of love, and community of feeling in regard to the worship of Almighty God, might be preserved among the highly favored multitude who compose the Catholic Church. And, inasmuch as this object could not be effectually and certainly secured, unless all, or at least the greater number of the bishops were to meet together, and a discussion of all particulars relating to our most holy religion to take place; for this reason as numerous an assembly as possible has been convened, at which I myself was present, as one among yourselves (and far be it from me to deny that which is my greatest joy, that I am your fellow-servant), and every question received due and full examination, until that judgment which God, who sees all things, could approve, and which tended to unity and concord, was brought to light, so that no room was left for further discussion or controversy in relation to the faith.
Chapter XVIII. He Speaks of Their Unanimity Respecting the Feast of Easter, and Against the Practice of the Jews.
"At this meeting the question concerning the most holy day of Easter was discussed, and it was resolved by the united judgment of all present, that this feast ought to be kept by all and in every place on one and the same day. For what can be more becoming or honorable to us than that this feast from which we date our hopes of immortality, should be observed unfailingly by all alike, according to one ascertained order and arrangement? And first of all, it appeared an unworthy thing that in the celebration of this most holy feast we should follow the practice of the Jews, who have impiously defiled their hands with enormous sin, and are, therefore, deservedly afflicted with blindness of soul. For we have it in our power, if we abandon their custom, to prolong the due observance of this ordinance to future ages, by a truer order, which we have preserved from the very day of the passion until the present time.
"Let us then have nothing in common with the detestable Jewish crowd; for we have received from our Saviour a different way. A course at once legitimate and honorable lies open to our most holy religion. Beloved brethren, let us with one consent adopt this course, and withdraw ourselves from all participation in their baseness. For their boast is absurd indeed, that it is not in our power without instruction from them to observe these things. For how should they be capable of forming a sound judgment, who, since their parricidal guilt in slaying their Lord, have been subject to the direction, not of reason, but of ungoverned passion, and are swayed by every impulse of the mad spirit that is in them? Hence it is that on this point as well as others they have no perception of the truth, so that, being altogether ignorant of the true adjustment of this question, they sometimes celebrate Easter twice in the same year. Why then should we follow those who are confessedly in grievous error? Surely we shall never consent to keep this feast a second time in the same year.
But supposing these reasons were not of sufficient weight, still it would be incumbent on your Sagacities to strive and pray continually that the purity of your souls may not seem in anything to be sullied by fellowship with the customs of these most wicked men. We must consider, too, that a discordant judgment in a case of such importance, and respecting such religious festival, is wrong. For our Saviour has left us one feast in commemoration of the day of our deliverance, I mean the day of his most holy passion; and he has willed that his Catholic Church should be one, the members of which, however scattered in many and diverse places, are yet cherished by one pervading spirit, that is, by the will of God. And let your Holinesses' sagacity reflect how grievous and scandalous it is that on the self-same days some should be engaged in fasting, others in festive enjoyment; and again, that after the days of Easter some should be present at banquets and amusements, while others are fulfilling the appointed fasts. It is, then, plainly the will of Divine Providence (as I suppose you all clearly see), that this usage should receive fitting correction, and be reduced to one uniform rule.
Chapter XIX. Exhortation to Follow the Example of the Greater Part of the World.
"Since, therefore, it was needful that this matter should be rectified, so that we might have nothing in common with that nation of parricides who slew their Lord: and since that arrangement is consistent with propriety which is observed by all the churches of the western, southern, and northern parts of the world, and by some of the eastern also: for these reasons all are unanimous on this present occasion in thinking it worthy of adoption. And I myself have undertaken that this decision should meet with the approval of your Sagacities, in the hope that your Wisdoms will gladly admit that practice which is observed at once in the city of Rome, and in Africa; throughout Italy, and in Egypt, in Spain, the Gauls, Britain, Libya, and the whole of Greece; in the dioceses of Asia and Pontus, and in Cilicia, with entire unity of judgment. And you will consider not only that the number of churches is far greater in the regions I have enumerated than in any other, but also that it is most fitting that all should unite in desiring that which sound reason appears to demand, and in avoiding all participation in the perjured conduct of the Jews.
In fine, that I may express my meaning in as few words as possible, it has been determined by the common judgment of all, that the most holy feast of Easter should be kept on one and the same day. For on the one hand a discrepancy of opinion on so sacred a question is unbecoming, and on the other it is surely best to act on a decision which is free from strange folly and error.
Chapter XX. Exhortation to Obey the Decrees of the Council.
"Receive, then, with all willingness this truly Divine injunction, and regard it as in truth the gift of God. For whatever is determined in the holy assemblies of the bishops is to be regarded as indicative of the Divine will. As soon, therefore, as you have communicated these proceedings to all our beloved brethren, you are bound from that time forward to adopt for yourselves, and to enjoin on others the arrangement above mentioned, and the due observance of this most sacred day; that whenever I come into the presence of your love, which I have long desired, I may have it in my power to celebrate the holy feast with you on the same day, and may rejoice with you on all accounts, when I behold the cruel power of Satan removed by Divine aid through the agency of our endeavors, while your faith, and peace, and concord everywhere flourish. God preserve you, beloved brethren."
The emperor transmitted a faithful copy of this letter to every province, wherein they who read it might discern as in a mirror the pure sincerity of his thoughts, and of his piety toward God.