The Council of Nicea in 325 set the celebration of Easter as the first Sunday after the first full moon following the spring equinox (March 21). The earliest possible date for Easter is March 22 and the latest April 25.

Calculation of Easter dates has always been complex and most people in previous centuries consulted tables prepared by church scholars. Similar calendars/tables are still found at the beginning of many printed prayer books. The date of Easter is a key date for calculating all of the moveable feasts that are connected with it e.g. Ascension and Pentecost so it is extremely important to know the correct date and to be able to have the date several years in advance.

There were many controversies in the early Church about how to calculate the date of Easter. Most of these were regionally based. Several of these controversies are outlined under the heading “Paschal Controversies” in the Oxford Dictionary of the Christian Church (3rd ed., 1997).

Today the Western and Eastern (Orthodox) Churches celebrate Easter on a different date. This difference is based on the reform of the secular calendar undertaken by Pope Gregory XIII in 1582. The Gregorian reform of the calendar meant the immediate “loss” of 10 days in 1582 in order to correct problems with the Julian Calendar worked out by Julius Caesar in 46 B.C. (England did not adopt the Gregorian Calendar until 1752 and then lost 12 days in September.) The “Orthodox Churches, even though most of them have adopted the Gregorian Calendar for fixed feasts, still calculate Easter according to the Julian Calendar, and, as their calculation of the Paschal full moon is five days later than the astronomical full moon, their Easter sometimes coincides with the Western date, but is often one, four or five weeks later” [1]. In the period 2001-2025 the Eastern and Western dates for Easter were/will be the same in seven years. The next year when the two will be the same is 2007 when Easter will be celebrated 8 April.[2]

In the twentieth century there have been a number of attempts to set either a fixed date for Easter e.g. the Sunday after the second Saturday in April or a common date i.e. agreed on by both the Eastern and Western churches. [3]. The debate has occurred primarily within the context of the World Council of Churches. “By celebrating this feast of feasts on different days, the churches give a divided witness to this fundamental aspect of the apostolic faith, compromising their credibility and effectiveness in bringing the Gospel to the world”. [4]

The 1998 Lambeth Conference discussed this subject and passed the following resolution IV:8 entitled “A Common Date for Easter”:

This Conference:

  1. welcomes the work of the WCC on a common date for Easter, recognising that in the year 2001, according to calculations by both the Eastern and Western Churches, the date of the Easter/Pascha observance will coincide; and
  2. recommends:
    1. that the following procedures for achieving a commonly recognised date for the annual celebration of Easter, as the day of resurrection of our Lord Jesus Christ, should be agreed upon by all Christian Churches:
      1. maintain the Nicene norms (that Easter fall on the Sunday following the first vernal new moon);
      2. calculate the date of the vernal equinox from the data provided by the most accurate scientific and astronomical methods;
      3. use as the basis of reckoning the meridian of Jerusalem, the place of Christ’s death and resurrection.
    2. that each province of the Anglican Communion be invited to endorse the above resolutions and to report its endorsement to the Secretary of the Anglican Consultative Council by the Feast of the Nativity, AD 2000 and that these responses be reported to the WCC. [5]

For a table of Easter dates up to and including the year 2025 see this page on Wikipedia.

[1] “Paschal Controversies” in Oxford Dictionary of the Christian Church. 3rd ed., rev. Edited by E.A. Livingston. Oxford: Oxford University Press, 1997. Page 1226.[2] Towards a Common Date for Easter : World Council of Churches/Middle East Council of Churches Consultation, Aleppo, Syria, March 5-10, 1997. Geneva: World Council of Churches, [1997]. See “Table for finding Easter/Pascha dates” on inside back cover.

[3] For the best summaries of the debate on this subject, see: Minutes of the Meeting of the Faith and Order Board 7-14 January 1996, Bangkok, Thailand. Commission on Faith and Order Paper No. 172. See Appendix 5 “A Common Date for the Celebration of Easter : History, Reflection, Proposals” By Dagmar Heller, pp. 119-132.

[4] Towards a Common Date for Easter : World Council of Churches/Middle East Council of Churches Consultation, Aleppo, Syria, March 5-10, 1997. Geneva: World Council of Churches, [1997]. Page 1.

[5] The Official Report of the Lambeth Conference 1998: Transformation and Renewal. Harrisburg PA: Published for the Anglican Communion by Morehouse Publishing, c1999. Page 409.