Anatolius of Alexandria: The Paschal Canon of Anatolius of Alexandria 11Chapter XI.

XI. Moreover, the allegation which they sometimes make against us, that if we pass the moon's fourteenth we cannot celebrate the beginning of the Paschal feast in light, neither moves nor disturbs us. For, although they lay it down as a thing unlawful, that the beginning of the Paschal festival should be extended so far as to the moon's twentieth; yet they cannot deny that it ought to be extended to the sixteenth and seventeenth, which coincide with the day on which the Lord rose from the dead. But we decide that it is better that it should be extended even on to the twentieth day, on account of the Lord's day, than that we should anticipate the Lord's day on account of the fourteenth day; for on the Lord's day was it that light was shown to us in the beginning, and now also in the end, the comforts of all present and the tokens of all future blessings. For the Lord ascribes no less praise to the twentieth day than to the fourteenth. For in the book of Leviticus the injunction is expressed thus: "In the first month, on the fourteenth day of this month, at even, is the Lord's Passover. And on the fifteenth day of this month is the feast of unleavened bread unto the Lord. Seven days ye shall eat unleavened bread. The first day shall be to you one most diligently attended and holy. Ye shall do no servile work thereon. And the seventh day shall be to you more diligently attended and holier; ye shall do no servile work thereon." And hence we maintain that those have contracted no guilt before the tribunal of Christ, who have held that the beginning of the Paschal festival ought to be extended to this day. And this, too, the most especially, as we are pressed by three difficulties, namely, that we should keep the solemn festival of the Passover on the Lord's day, and after the equinox, and yet not beyond the limit of the moon's twentieth day.