Editing Reform of the date of Easter (section)

==Description==
A reform of the date of Easter has been proposed several times<ref>{{cite thesis| last= Marcello| first= Albert| date= 2024| title= The date of Easter: classical considerations and contemporary challenges | url= https://ruor.uottawa.ca/server/api/core/bitstreams/300383f1-5612-4680-b15a-d4112434713c/content| degree= Doctorate of Philosophy in Canon Law| chapter= 2.1 Medieval Reform Proposals| publisher= Saint Paul University, Faculty of Canon Law | location= Ottawa, Ontario, Canada| access-date= 2024-12-09}}<!--docket= | oclc= | --></ref> because the current system for determining the date of [[Easter]] is seen as presenting two significant problems:
# Its [[moveable feast|date varies from year to year]]. It can fall on up to 35 days in March and April of the respective calendar. While many Christians do not consider this to be a problem, it can cause frequent difficulties of co-ordination with [[civil calendar]]s, for example [[academic term]]s. Many countries have [[public holiday]]s around Easter weekend or tied to the date of Easter but spread from February to June, such as [[Shrove Tuesday]] or [[Feast of the Ascension|Ascension]] and [[Pentecost]].
# Some [[Eastern Christianity|Eastern churches]] (6 in total) calculate the date of Easter using the [[Julian calendar]], whereas most Eastern churches use the [[Revised Julian calendar]] and all [[Western Christianity|Western churches]] and civil authorities have adopted the [[Gregorian calendar|Gregorian reforms]] for all calendrical purposes. Also a very few [[Eastern Christianity|Eastern churches]] have adopted the Gregorian method of calculation. Hence in most years, Easter is celebrated on a later date in the East than in the West.

There have been [[Easter controversy|controversies about the "correct" date of Easter]] since antiquity, but most Christian churches today agree on certain points. The Roman Catholic Church explains:<ref>{{cite news|url=http://www.catholicweekly.com.au/why-dont-catholics-and-orthodox-celebrate-easter-on-same-date|last=Flader|first=John|title=Why don't Catholics and Orthodox celebrate Easter on same date?|newspaper=Catholic Weekly|location=Sydney|date=9 March 2016|accessdate=22 July 2023}}</ref>

{{blockquote|The [[First Council of Nicaea#Separation of Easter computation from Jewish calendar|Council of Nicaea in 325]] determined, among other things, that the Church would no longer follow the Jewish calendar and that Easter was to be celebrated on a common day throughout the world. (…)
The council did not say what that day was to be but at the time Easter was celebrated on a Sunday virtually everywhere.}}

To justify his calendar reform, which involved removing ten days, in 1582 [[Pope Gregory XIII]] claimed that the council had decreed that Easter should be celebrated:
* on a [[Sunday]],
* after the nominal [[Northward equinox]] – that is the start of spring in the Northern and of autumn in the Southern Hemisphere, fixed on 21 March in the Gregorian calendar –,
* after the first [[ecclesiastical full moon]] of the astronomical season.

There is less agreement whether Easter also should occur:
* so that [[Feast of the Annunciation|Annunciation]] – celebrated 25 March, 9 months before [[Christmas]] – does not fall on any day from the [[Palm Sunday|Sunday before Easter]] to the [[Octave of Easter|Sunday after]],
* on or after the [[Quartodecimanism|14th day]] of the lunar month of [[Nisan]],
* not before [[Passover|Jewish Pesach]] – Easter is after [[Christian observance of Passover|Christian Passover]] by definition.

The disagreements have been particularly about the determination of moon phases and the equinox, some preferring astronomical observation from a certain location (usually Jerusalem, Alexandria, Rome or local), most others following nominal approximations of these in either the [[Hebrew calendar|Hebrew]], Julian or Gregorian calendar using different lookup tables and cycles in their algorithms. Deviations may also result from different customs for the start of the ''[[day]]'', i.e. dusk, sunset, midnight, dawn or sunrise. Furthermore, it may be accepted to have the respective starts of the astronomical season, the full moon and the Sunday occur on the same date as long as they are observed in that order.