Chapter 17: The cycle of Easter

10. After the completion of this [95-year cycle][313] a return must be made to the beginning. In ancient times the church used to celebrate Easter on the 14th of the moon at the same time as the Jews, whatever day it came on; this way of celebrating the holy Fathers forbade at the council of Nicaea, giving directions to make inquiry not only for the Easter moon and month, but also to observe the day of the resurrection of the Lord, and because of this they extended Easter from the 14th of the moon to the 21st, in order that the _dies Dominicus_ might not be left out.

[313] This passage is preceded by a table indicating the date
of Easter for 95 years (627–721). It is clear that although
Isidore was not acquainted with the plan of Dionysius Exiguus
to institute the Christian era, he was acquainted with the
essentials of his Easter table. Dionysius had given the dates
for Easter in five 19-year cycles, dating from 525; in Isidore
this is continued for the years 627 to 721. Isidore’s table
consists merely of parallel columns of the days of the month
and corresponding days of the moon on which Easter fell. Each
date is marked C or E, abbreviations for _communis annus_ and
_embolismus_ which describe respectively the year of twelve and
that of thirteen lunar months in use in the Hebrew chronology.
A further abbreviation, B, stands opposite each fourth year, to
mark the leap-years. The years are not numbered according to
any era, and the assignment of dates, 627–721, is inferred from
the dates given for Easter. See Ideler, _Chronologie_, vol. ii,
p. 290 (Berlin, 1826). Isidore does not make it plain that he
understood the mathematics of the computation of Easter. It is
of interest that in 643 the fourth synod of Toledo passed an
enactment to secure a common observance of Easter throughout the
Spanish churches, no doubt according to this Easter-table. See
Gams, _Die Kirchengeschichte von Spanien_ (Regensburg, 1874),
vol. ii, part 2, p. 94.

12. The eve of Easter is spent in watching because of the coming of our King and God, that the time of the resurrection may find us not sleeping but waking. And the reason for this night is a double one, either because he received life at that time when he suffered, or because he is to come for judgment at the same hour at which he arose.

13. And we celebrate Easter in such a way as not merely to call to memory the death and resurrection of Christ but also to consider the rest that is told about him with reference to its mystic meaning (_ad sacramentorum significationem_).

14. For on account of beginning the new life, and on account of the new man which we are bidden to put on and to put off the old, purging away the old ferment in order that we may be a new sprinkling (_conspersio_), since Christ is sacrificed as our Pascha (Passover); on account of this newness of life, then, the first month in the months of the year is mystically assigned to the Easter festival.

15. And that Easter is celebrated on a day in the third week, that is, a day that occurs between the fourteenth and twenty-first, this signifies that in the whole time of the world, which is based on the unit of seven days, this mystery has now opened a third time.

16. For the first time is before the law, the second under the law, the third under grace. Wherein the mystery before hidden in the prophetic allegory is now plain, and the resurrection of the Lord is on the third day on account of these three periods of the world.

17. As to the fact that Easter day is sought through seven days from the fourteenth to the twenty-first, this is done on account of the number seven, by which the meaning of completeness is often figured, which is also assigned to the church itself because it is universal. For this reason also John, the apostle, writes to the seven churches.

18. And by the name of the moon in the Scriptures, on account of its mutability it is signified that the church as yet is established [only] in the mortality of the flesh.

19. An observance of different opinions as to the feast of Easter sometimes produces error. For the Latins seek for the moon of the first month from the third day before the Nones of March to the third before the Nones of April, and if the fourteenth day of the moon comes on Sunday, they postpone Easter to another Sunday.

20. The Greeks observe the moon of the first month from the eighth before the Ides of March to the day of the Nones of April, and if the fifteenth day of the moon comes on the Lord’s day, they celebrate Easter. A difference of this sort between them disturbs the regularity of the Easter canon.