Easter Day moves around all over the calendar. And with it everything from Ash Wednesday to the Day of Pentecost. The dating of Easter arises from the complicated joining of two different calendar systems. These calendars might be illustrated by the early story of Cain and Abel. If you are an Abel type – hunting, fishing, watching your flock by night, you will focus on the moon and the lunar cycle of 29 and a half days. Moonlight and tides will be significant to you. If you are a Cain type, a tiller of the ground and grower of crops, the solar cycle and its seasons will be more significant to you. The dating of Easter comes out of combining these solar and lunar calendars.
This post will primarily focus on the Western (Gregorian Calendar) way of dating Easter.
Passover – Pesach
The Jewish calendar is lunar. Twelve lunar months, with an occasional extra month popped in to keep up with the solar year. The month begins with new moon, and full moon, in the middle of the month, is the obvious time for extensive parties and festivals. There’s more light at night! Passover (Pesach) is the first full moon after the vernal (Northern Spring) equinox (14 of Abib in the Old Testament’s Hebrew Calendar) (Lev 23:5). This was to be a “perpetual ordinance” (Exodus 12:14).
Nicaea on Easter
There appears confusion between the synoptics (Matthew, Mark, and Luke) and John on the relationship between the Passover celebration and Christ’s death. Added to that, some early Christians celebrated Pascha (Easter) on the Jewish festival of Passover, whilst others always celebrated it on the Sunday following. The former were called Quartodecimans (Latin: quarta decima, fourteen). The Council of Nicaea (325) decided against the Quartodecimans and in favour of Easter always being on a Sunday. Rather than produce a canon on this, they communicated this to the different dioceses and gave the Bishop of Alexandria the privilege of announcing annually the date of Easter.
The Council of Nicaea determined that Easter would be the Sunday which follows the first full moon after the vernal equinox. If full moon happens to fall on Sunday, Easter is celebrated the following Sunday. Furthermore, it fixed the vernal equinox to be 21 March.
By the sixth century complex mathematical methods had been devised, involving paschal cycles of 19 years in the East, and 84 years in the West. Hence Easter calculations are based not on the astronomical full moon but an “ecclesiastical moon,” based on these created tables.
The Gregorian Calendar
A further divergence developed when there was a growing realisation of the drifting of the Julian Calendar from the actual solar year. In the Julian Calendar every year divisible by four is a leap year. This actually makes the Julian year slightly too long. By the sixteenth century this drift had made 10 days of difference. Pope Gregory in 1582 declared that October 4th would be followed by October 15th, and that only centuries divisible by 400 would be a leap year. This is known as the Gregorian calendar most now use. 1900 was not a leap year, but 2000 was a leap year. England, not under the authority of the pope, did not change to the Gregorian calendar until 1752 and there were riots demanding the giving back of the (by then) 12 days lost! The Eastern part of the church continues to calculate its festivals by the Julian calendar.
Easter in the future?
There has been discussion about abandoning any relationship with the lunar cycle and fixing Easter on the Sunday after the second Saturday in April. The Second Vatican Council agreed to a fixed date for Easter provided a consensus could be reached among Christian churches.
There was an ecumenical meeting in Aleppo, Syria in 1997. This concluded that the present differences in the calendars and lunar tables (paschal cycles) have no different fundamental theological outlook. The suggestion there was to replace both Eastern and Western calculations with the most advanced astronomically accurate calculations of the equinox and the full moon following, using the meridian of Jerusalem as the point of measure. This has not advanced further.
If there are any errors in this article, please let me know.
This year Passover is April 9 (sundown 8 April) to April 16, 2009 (at sundown) (5769). Easter Day for Western churches is April 12, 2009. And for Eastern churches it is a week later – April 19, 2009.
Easter can occur anywhere between March 22 and April 25.
Thank you, Bosco. This is very clear and informative. it would certainly be nice if we could all celebrate East on the same date. Easter joy to you, Mike+
Thanks for a superb explanation! Would not all educators in NZ (at least) rise up and say, Amen, to Easter being fixed to the Sunday after the second Saturday in April?
I was trying to explain this to someone at work the other day who found it utterly baffling – if only I’d had this post to hand then!
I’d find it a shame if they fixed the date of Easter each year; surely there is a historical link to the Passover we’d miss if they did?
Anyway, your post brought back happy memories of trying to decipher those obscure tables at the front of the Book of Common Prayer. Take the year… divide by the age of your granny; add the number you first thought of and then convert it into a letter…
If the date of Easter were on a fixed date, I think it would be a theological loss. The calculation currently connects to both solar and lunar calendars–it’s a symbolic way for all of creation to participate in the Paschal celebration! It also reminds us humans that we are part of creation, and we too must participate with the cosmos in the vigiling to Easter.
Happy Easter…Thank you for Shepherding your brothers and sisters, on Twitter, through Holy Week. “In his heart a man plans his course, but the Lord determines his steps”. Proverbs 16:9, God be with you….Pixie
I’m James (@jpc101 on twitter) and I run http://www.whyeaster.com. Thanks for the article! If people fancy doing some maths, have a read of: http://www.whyeaster.com/customs/dateofeaster.shtml
Keep up the great work Bosco!
Happy Easter.
You wrote:
“Some early Christians celebrated Pascha (Easter) on the Jewish festival of Passover, whilst others always celebrated it on the Sunday following. The former were called Quartodecimans (Latin: quarta decima, fourteen). The Council of Nicaea (325) decided against the Quartodecimans and in favour of Easter always being on a Sunday. Rather than produce a canon on this, they communicated this to the different dioceses and gave the Bishop of Alexandria the privilege of announcing annually the date of Easter.”
The Quartodeciman practice was not the issue at Nicea (though some scholars have thought so.) Rather, the Easter controversy at Nicea was between “Jewish calendarists” who wanted to continue the old custom of setting Easter to the 3rd Sunday of Nisan as computed by the Jewish calendar, and “independent calendarists” who wanted to compute the Paschal lunar month (in effect, a Christian Nisan) independently of the Jewish calendar, and set Easter to the 3rd Sunday within that independently computed lunar month. The “Jewish calendarists” claimed to have tradition on their side. The “independent calendarists” claimed that it was the Jewish calendar that had broken with its own earlier traditions by not enforcing a rule that the week of Unleavened Bread should always fall after the spring equinox. (The modern Hebrew calendar always puts the week of Unleavened Bread after the equinox, but the modern Hebrew calendar did not yet exist in the 3rd-4th centuries.) Nicea sided with the “independent calendarists.” Henceforward Christians would compute their own, Christian Nisan, and their own, Christian, Week of Unleavened Bread, and set Easter to the Sunday in that week. The older custom (later called “protopaschite”) was deprecated, but some stuck to it for a time.
I have not found any evidence that the Nicene council officially “gave the Bishop of Alexandria the privilege of announcing annually the date of Easter” to the Bishop of Alexandria. In actual practice, the Bishops of Rome and Alexandria were in constant communication, and their agreed dates were widely used due to the great prestige of these two sees. In later centuries, it was the Alexandrian computus that prevailed over other systems, so in that very roundabout way, it was indeed the bishop of Alexandria who had the last word.
You also write
“Passover (Pesach) is the first full moon after the vernal (Northern Spring) equinox (14 of Abib in the Old Testament’s Hebrew Calendar) (Lev 23:5).”
This is technically correct. The Passover strictly so-called is the 14th of Nisan, in the afternoon of which the Passover lamb was slaughtered. The 15th, after sunset, when the lamb was eaten, is the first Day of Unleavened Bread. However, you also write, later on,
“This year Passover is April 9 (sundown 8 April) to April 16, 2009 (at sundown) (5769).”
Here you are using the word Passover to mean the 1st day of Unleavened Bread, 15 Nisan, which, in modern times, is almost always called “Passover.” But this usage is inconsistent with the more precise scriptural usage you employ earlier in the article.
You also write,
“By the sixth century complex mathematical methods had been devised, involving paschal cycles of 19 years in the East, and 84 years in the West. Hence Easter calculations are based not on the astronomical full moon but an “ecclesiastical moon,” based on these created tables.”
Again, this is true, but not quite the whole story. The western 84-year cycles were eventually displaced by the Alexandrian 19-year cycle used in the East, and it is 19-year cycles that continue to be used today, in both Christian lunar calendars and in the Jewish calendar.
You write also,
“The Jewish calendar is lunar. Twelve lunar months, with an occasional extra month popped in to keep up with the solar year. The month begins with new moon.”
and,
“Easter calculations are based not on the astronomical full moon but an ‘ecclesiastical moon,’ based on these created tables.”
Both statements are true, but I think it makes things clearer to point out that the “Ecclesiastical moon” used to compute Easter can be described by precisely the same words you apply to the Jewish calendar. The Ecclesiastical moon is a lunar calendar, whose lunar months have 30 or 29 days and begin with the new moon. If desired, its 19-year cycle can even be sorted into 12 years of 12 lunar months, and 7 years with an extra, 13th lunar month “popped in”. Today, April 12th, 2009, is the 16th day of the lunar month in the Gregorian lunar calendar. In the Julian lunar calendar, it is the 12th. So western Christianity is already in what might be called its Week of Unleavened Bread (the 15th to the 21st of the lunar month) while for the easterners the moon won’t be full until Tuesday.
Here is another helpful article, particularly clarifying the confusion that although with current calendars, Eastern Easter always comes after the Jewish Passover, that is because, coincidentally, the Julian calendar and the Hebrew calendar are both astronomically inaccurate in similar ways:
http://catholicism.about.com/b/2009/04/16/reader-question-is-the-date-of-easter-related-to-passover.htm
Have you read “Sitting at The Feet of Rabbi Jesus” by Ann Spangler, Lois Tverberg? I found this book at the beginning of Lent and just loved reading it! I’ve already passed it on to a friend.
here is the synopsis:
Sitting at the Feet of Rabbi Jesus takes readers on a fascinating journey, helping them discover how learning about the Jewish world of Jesus can enrich their own faith. By exploring the land, culture, customs, prayers, and feasts, Ann Spangler and Lois Tverberg help readers to perceive Jesus through the eyes and ears of first-century Jews.