Originally Posted by Oracle of Wiki
Easter is the most important religious feast in the Christian liturgical year.[1] It is believed by the Christians to be the resurrection of Jesus, which Christians believe occurred on the third day after his crucifixion around AD 33. Many non-religious cultural elements have become part of the holiday, and those aspects are often celebrated by many Christians.
Easter is termed a moveable feast because it is not fixed in relation to the civil calendar. Easter falls at some point between late March and late April each year (early April to early May in Eastern Christianity), following the cycle of the moon. After several centuries of disagreement, all churches accepted the computation of the Alexandrian Church (now the Coptic Church) that Easter is the first Sunday after the first fourteenth day of the moon (the Paschal Full Moon) that is on or after the ecclesiastical vernal equinox.
Easter is linked to the Jewish Passover not only for much of its symbolism but also for its position in the calendar. The Last Supper shared by Jesus and his disciples before his crucifixion is generally thought of as a Passover meal, based on the chronology in the Synoptic Gospels (Matthew 26:17; Mark 14:12; Luke 22:7). The Gospel of John, however, speaks of the Jewish elders not wanting to enter the hall of Pilate in order "that they might eat the Passover", implying that the Passover meal had not yet occurred (John 18:28; John 19:14).[2] Thus, John places Christ's death at the time of the slaughter of the Passover lamb, which would put the Last Supper slightly before Passover, on 14 Nisan of the Bible's Hebrew calendar.[3] According to The Catholic Encyclopedia, "In fact, the Jewish feast was taken over into the Christian Easter celebration."
Easter and the holidays that are related to it are moveable feasts, in that they do not fall on a fixed date in the Gregorian or Julian calendars (both of which follow the cycle of the sun and the seasons). Instead, the date for Easter is determined on a lunisolar calendar, as is the Hebrew calendar.
In Western Christianity, Easter always falls on a Sunday between March 22 and April 25 inclusively.[17] The following day, Easter Monday, is a legal holiday in many countries with predominantly Christian traditions. In the Julian calendar used by Eastern Christianity, Easter also always falls on a Sunday from March 22 to April 25 inclusive, which in the Gregorian calendar, due to the 13 day difference between the calendars between 1900 and 2099, are dates from April 4 to May 8 inclusive.
The precise date of Easter has at times been a matter for contention. At the First Council of Nicaea in 325 it was decided that all Christians would celebrate Easter on the same day, which would be a Sunday. It is probable that no method of determining the date was specified by the Council. (No contemporary account of the Council's decisions has survived.) Instead, the matter seems to have been referred to the church of Alexandria, which city had the best reputation for scholarship at the time. Epiphanius of Salamis wrote in the mid-4th Century:
"...the emperor...convened a council of 318 bishops...in the city of Nicea...They passed certain ecclesiastical canons at the council besides, and at the same time decreed in regard to the Passover that there must be one unanimous concord on the celebration of God's holy and supremely excellent day. For it was variously observed by people...".[18]
The Council of Nicaea, however, did not declare the Alexandrian or Roman calculations as normative. Instead, the council gave the Bishop of Alexandria the privilege of announcing annually the date of Christian Passover to the Roman curia. Although the synod undertook the regulation of the dating of Christian Passover, it contented itself with communicating its decision to the different dioceses, instead of establishing a canon. Its exact words were not preserved, but from scattered notices the council ruled:
* that Easter must be celebrated by all throughout the world on the same Sunday;
* that this Sunday must follow the fourteenth day of the paschal moon;
* that the moon was to be accounted the paschal moon whose fourteenth day followed the vernal equinox;
* that some provision should be made, probably by the Church of Alexandria as best skilled in astronomical calculations, for determining the proper date of Easter and communicating it to the rest of the world.
It took a while for the Alexandrian rules to be adopted throughout Christian Europe. The Church of Rome continued to use an 84-year lunisolar calendar cycle from the late third century until 457. The Church of Rome continued to use its own methods until the 6th century, when it may have adopted the Alexandrian method as converted into the Julian calendar by Dionysius Exiguus (certain proof of this does not exist until the ninth century). Early Christians in Britain and Ireland also used a late third century Roman 84-year cycle until the Synod of Whitby in 664, when they adopted the Alexandrian method. Churches in western continental Europe used a late Roman method until the late 8th century during the reign of Charlemagne, when they finally adopted the Alexandrian method. However, with the adoption of the Gregorian calendar by the Catholic Church in 1582 and the continuing use of the Julian calendar by Eastern Orthodox Churches, the date on which Easter is celebrated again deviated, and continues to this day.
The rule has since the Middle Ages been phrased as Easter is observed on the Sunday after the first full moon on or after the day of the vernal equinox. However, this does not reflect the actual ecclesiastical rules precisely. One reason for this is that the full moon involved (called the Paschal full moon) is not an astronomical full moon, but an ecclesiastical moon. Another difference is that the astronomical vernal equinox is a natural astronomical phenomenon, while the ecclesiastical vernal equinox is a fixed March 21. Easter is determined from tables which determine Easter based on the ecclesiastical rules described above, which approximate the astronomical full moon.
In applying the ecclesiastical rules, the various Christian Churches use 21 March as their starting point from which they find the next full moon, etc. However because Eastern Orthodox and Oriental Orthodox Churches use the Julian Calendar as their starting point, while Western Christianity uses the Gregorian Calendar, the end point, the date for Easter, may diverge.
