Easter

When early Christian monks and missionaries started spreading their new faith across Europe, many of them found that although converts could be won easily enough, many continued to worship their old gods as much as the new ones. Gradually the old pagan beliefs about rebirth and renewal became intricately entwined with Christian ideas of resurrection, and many of the old pagan ideas still live on in our modern Easter traditions:

• Hot Cross Buns: an ox would often be sacrificed at the festival of Eostre, and the Saxon word for "ox" is "boun". The bread which was baked for the ceremony used to have symoblic ox's horns shaped in it; these became converted to a more Christian cross.
• Easter Egg: probably the most obvious fertility symbol, an egg is an instant reminder of more ancient Spring equinox ceremonies.
• Easter Bunny: another image associated with fertility and reproduction, the rabbit also harks back to older rites.

Year    Astron.    Greg.      Julian     Vernal     Pesach
2001   15 April   15 April   15 April    8 April    8 April 
2002   31 March   31 March    5 May     28 March   28 March
2003   20 April   20 April   27 April   16 April   17 April
2004   11 April   11 April   11 April    5 April    6 April
2005   27 March   27 March    1 May     25 March   24 April
2006   16 April   16 April   23 April   13 April   13 April
2007    8 April    8 April    8 April    2 April    3 April
2008   23 March   23 March   27 April   21 March   20 April
2009   12 April   12 April   19 April    9 April    9 April
2010    4 April    4 April    4 April   30 March   30 March
2011   24 April   24 April   24 April   18 April   19 April
2012    8 April    8 April   15 April    6 April    7 April
2013   31 March   31 March    5 May     27 March   26 March
2014   20 April   20 April   20 April   15 April   15 April
2015    5 April    5 April   12 April    4 April    4 April
2016   27 March   27 March    1 May     23 March   23 April
2017   16 April   16 April   16 April   11 April   11 April
2018    1 April    1 April    8 April   31 March   31 March
2019   24 March   21 April   28 April   21 March   20 April
2020   12 April   12 April   19 April    8 April    9 April
2021    4 April    4 April    2 May     28 March   28 March
2022   17 April   17 April   24 April   16 April   16 April
2023    9 April    9 April   16 April    6 April    6 April
2024   31 March   31 March    5 May     25 March   23 April
2025   20 April   20 April   20 May     13 April   13 April

The date of the Easter Sunday can be calculated using the following method derived from the original algorithm by Carl Friedrich Gauss. The algorithm can be applied to the Gregorian calendar for years 1900-2099. The date given by the algorithm is used in Western Christian churches, the date used by the Eastern churches can be 1, 4 or 5 weeks later. More comprehensive forms (including years 1583-9999) of the algorithm exist but they include lenghty tables of Epact and Sunday Letter constants so I won't add them here.

a = year mod 19 (use year in four digits)
b = year mod 4
c = year mod 7
d = (24+19a) mod 30
e = (5+2b+4c+6d) mod 7
Easter Sunday is on the (22+d+e) of March or on the (d+e-9) of April, depending on which answer is a valid date. If the date given by the algorithm is 26th of April, the Easter Sunday is on 19th of April. If the date is 25th of April and d=28 and a>10, the Easter Sunday is on 18th of April.

By George Herbert

I Got me flowers to straw Thy way,
I got me boughs off many a tree;
But Thou wast up by break of day,
And brought'st Thy sweets along with Thee.

Yet though my flowers be lost, they say
A heart can never come too late;
Teach it to sing Thy praise this day,
And then this day my life shall date.

As mentioned in omega's w/u there's a more comprehensive form of the algorithm for calculating Easter dates. The method below has been given by Spencer Jones in his book General Astronomy. Unlike the formula given by Gauss, this method has no exception and is valid for all years in the Gregorian calendar, that is from the year 1583 on. The procedure for determining the date of Easter is as follows:

  Divide                  by     Quotient     Remainder


the year x                19         -            a

the year x               100         b            c

b                          4         d            e

b + 8                     25         f            -

b - f + 1                  3         g            -

19a + b - d - g + 15      30         -            h

c                          4         i            k

32 + 2e + 2i - h - k       7         -            l

a + 11h + 22l            451         m            -

h + l - 7m + 114          31         n            p

Then n = number of the month (3 = March, 4 = April), p + 1 = day of that month upon which Easter Sunday falls.

If you want to use this formula in a computer program, the calculation of the remainder of a division must be programmed carefully. Suppose that the remainder of the division of 34 by 30 should be found. For instance we find

34/30 = 1.133 333 333

the fractional part of which is 0.133 333 333. When multiplied by 30, this gives 3.999 999 990. This result differs from 4, the correct value, and may give a wrong date for Easter at the end of the calculation. So it's necessary to use some programming trick (a rounding of some sort on the remainder should work fine in most cases I guess) to avoid this problem.

As knifegirl observed above, Easter Sunday varies from year to year. In 1800, the mathematician Karl Friedrich Gauss devised the following algorithm to determine the date of Easter Sunday (for Western churches) for a given year.

• Let y be the year for which you wish to find Easter Sunday.
• Divide y by 19 and call the remainder a. (ignore the quotient)
• Divide y by 100 to obtain a quotient b and a remainder c.
• Divide b by 4 to get a quotient d and a remainder e.
• Calculate 8*b + 13. Then divide by 25 to get a quotient g. (ignore the remainder)
• Calculate 19*a +b -d -g +15. Then divide by 30 to get a remainder h. (ignore the quotient)
• Divide c by 4 to get a quotient j and a remainder k.
• Calculate a + 11*h. Divide by 319 to get a quotient m. (ignore the remainder)
• Calculate 2*e + 2*j -k -h +m +32. Divide by 7 to get a remainder r. (ignore the quotient)
• Calculate h -m +r +90. Divide by 25 to obtain a quotient n. (ignore the remainder)
• Calculate h -m +r +n +19. Divide by 32 to get a remainder p. (ignore the quotient)

Then, Easter Sunday for year y falls on day p of month n.

Obviously, this is somewhat tedious to do by hand each time, so if you're just interested in the destination rather than the journey I wrote a (probably very bad and largely untested) java applet to do this which can be found at http://www.bath.ac.uk/~ma2gdt/easter.html .

Eas"ter (?), n. [AS. easter, eastran, paschal feast, Easter; akin to G. ostern; fr. AS. Eastre, a goddess of light or spring, in honor of whom a festival was celebrated in April; whence this month was called in AS. Eastermna. From the root of E. east. See East.]

1.

An annual church festival commemorating Christ's resurrection, and occurring on Sunday, the second day after Good Friday. It corresponds to the pasha or passover of the Jews, and most nations still give it this name under the various forms of pascha, pasque, paque, or pask.

2.

The day on which the festival is observed; Easter day.

Easter is used either adjectively or as the first element of a compound; as, Easter day or Easter-day, Easter Sunday, Easter week, Easter gifts.

Sundays by thee more glorious break, An Easter day in every week. Keble.

Easter day, on which the rest of the movable feasts depend, is always the first Sunday after the fourteenth day of the calendar moon which (fourteenth day) falls on, or next after, the 21st of March, according to the rules laid down for the construction of the calendar; so that if the fourteenth day happen on a Sunday, Easter day is the Sunday after.

Eng. Cyc.

Easter dues Ch. of Eng., money due to the clergy at Easter, formerly paid in communication of the tithe for personal labor and subject to exaction. For Easter dues, Easter offerings, voluntary gifts, have been substituted. -- Easter egg. (a) A painted or colored egg used as a present at Easter. (b) An imitation of an egg, in sugar or some fine material, sometimes made to serve as a box for jewelry or the like, used as an Easter present.

© Webster 1913.

East"er (?), v. i. Naut.

To veer to the east; -- said of the wind.

Russell.

© Webster 1913.