Name of Easter
The origins of the word "Easter" are not certain, but probably derive from Estre, an Anglo-Saxon goddess of spring The German word Ostern has the same derivation, but most other languages follow the Greek term used by the early Christians: pascha, from the Hebrew pesach (Passover).
In Latin, Easter is Festa Paschalia (plural because it is a seven-day feast), which became the basis for the French Pââques, the Italian Pasqua, and the Spanish Pascua. Also related are the Scottish Pask, the Dutch Paschen, the Danish Paaske, and the Swedish Pask.
Date of Easter
The method for determining the date of Easter is complex and has been a matter of controversy (see History of Easter, below). Put as simply as possible, the Western churches (Catholic and Protestant) celebrate Easter on the first Sunday following the first full moon after the spring equinox.
But it is actually a bit more complicated than this. The spring equinox is fixed for this purpose as March 21 (in 2004, it actually falls on March 20) and the "full moon" is actually the paschal moon, which is based on 84-year "paschal cycles" established in the sixth century, and rarely corresponds to the astronomical full moon. These complex calculations yield an Easter date of anywhere between March 22 and April 25.
The Eastern churches (Greek, Russian, and other forms of Orthodoxy) use the same calculation, but based on the Julian calendar (on which March 21 is April 3) and a 19-year paschal cycle.
Thus the Orthodox Easter sometimes falls on the same day as the western Easter (it does in 2004), but the two celebrations can occur as much as five weeks apart.
In the 20th century, discussions began as to a possible worldwide agreement on a consistent date for the celebration of the central event of Christianity. No resolution has yet been reached.
The specific day on which the resurrection should be celebrated became a major point of contention within the church. First, should it be on Jewish Passover no matter on what day that falls, or should it always fall on a Sunday? It seems Christians in Asia took the former position, while those everywhere else insisted on the latter. The eminent church fathers Irenaeus and Polycarp were among the Asiatic Christians, and they claimed the authority of St. John the Apostle for their position. Nevertheless, the church majority officially decided that Easter should always be celebrated on a Sunday. Eusebius of Caesarea, our only source on this topic, reports the affair as follows:
A question of no small importance arose at that time [c. 190 AD]. The dioceses of all Asia, as from an older tradition, held that the fourteenth day of the moon, on which day the Jews were commanded to sacrifice the lamb, should always be observed as the feast of the life-giving pasch, contending that the fast ought to end on that day, whatever day of the week it might happen to be. However it was not the custom of the churches in the rest of the world to end it at this point, as they observed the practice, which from Apostolic tradition has prevailed to the present time, of terminating the fast on no other day than on that of the Resurrection of our Saviour. Synods and assemblies of bishops were held on this account, and all with one consent through mutual correspondence drew up an ecclesiastical decree that the mystery of the Resurrection of the Lord should be celebrated on no other day but the Sunday and that we should observe the close of the paschal fast on that day only.With this issue resolved, the next problem was to determine which Sunday to celebrate the resurrection. The Christians in Syria and Mesopotamia held their festival on the Sunday after the Jewish Passover (which itself varied a great deal), but those in Alexandria and other regions held it on the first Sunday after the spring equinox, without regard to the Passover.
This second issue was decided at the Council of Nicea in 325, which decreed that Easter should be celebrated by all on the same Sunday, which Sunday shall be the first following the paschal moon (and the paschal moon must not precede the spring equinox), and that a particular church should determine the date of Easter and communicate it throughout the empire (probably Alexandria, with their skill in astronomical calculations).
The policy was adopted throughout the empire, but Rome adopted an 84-year lunar cycle for determining the date, whereas Alexandria used a 19-year cycle. } Use of these different "paschal cycles" persists to this day and contributes to the disparity between the eastern and western dates of Easter.