Easter, the principal festival of the Christian church year, celebrates the Resurrection of Jesus Christ on the third day after his Crucifixion. The origins of Easter date to the beginnings of Christianity, and it is probably the oldest Christian observance after the Sabbath (observed on Saturday). Later, the Sabbath subsequently came to be regarded as the weekly celebration of the Resurrection.
Meanwhile, many of the cultural historians find, in the celebration of Easter, a convergence of the three traditions - Pagan, Hebrew and Christian.
According to St. Bede, an English historian of the early 8th century, Easter owes its origin to the old Teutonic mythology. It was derived from the name Eostre, the Anglo-Saxon goddess of spring, to whom the month of April was dedicated. The festival of Eostre was celebrated at the vernal equinox, when the day and night gets an equal share of the day.
The English name "Easter" is much newer. When the early English Christians wanted others to accept Christianity, they decided to use the name Easter for this holiday
so that it would match the name of the old spring celebration. This made it more comfortable for other people to accept Christianity.
But it is pointed out by some that the Easter festival, as celebrated today, is related with the Hebrew tradition, the Jewish Passover. This is being celebrated during Nisan, the first month of the Hebrew lunar year. The Jewish Passover under Moses commemorates Israel's deliverance from about 300 years of bondage in Egypt.
It was in during this Passover in 30 AD Christ was crucified under the order of the Roman governor Pontius Pilate as the then Jewish high priests accused Jesus of "blasphemy". The resurrection came three days later, on the Easter Sunday. The early Christians, many of them being brought up in Jewish tradition regarded Easter as a new feature of the Pascha (Passover). It was observed in memory of the advent of the Messiah, as foretold by the prophets. And it is equanimous with the proclamation of the resurrection. Thus the early Christian Passover turned out to be a unitive celebration in memory of the passion-death-resurrection of Jesus. However, by the 4th century, Good Friday came to be observed as a separate occasion. And the Pascha Sunday had been devoted exclusively to the honor of the glorious resurrection.
Throughout the Christendom the Sunday of Pascha had become a holiday to honor Christ. At the same time many of the pagan spring rites came to be a part of its celebration. May be it was the increasing number of new converts who could not totally break free of the influence of pagan culture of their forefathers.
But despite all the influence there was an important shift in the spirit. No more glorification of the physical return of the Sun God. Instead the emphasis was shifted to the Sun of Righteousness who had won banishing the horrors of death for ever.
The Feast of Easter was well established by the second century. But there had been dispute over the exact date of the Easter observance between the Eastern and Western Churches. The East wanted to have it on a weekday because early Christians observed Passover every year on the 14th of Nisan, the month based on the lunar calendar. But, the West wanted that Easter should always be a Sunday regardless of the date.
To solve this problem the emperor Constantine called the Council of Nicaea in 325. The question of the date of Easter was one of its main concerns. The council decided that Easter should fall on Sunday following the first full moon after the vernal equinox. But fixing up the date of the Equinox was still a problem. The Alexandrians, noted for their rich knowledge in astronomical calculations were given the task. And March 21 was made out to be the perfect date for spring equinox.
The dating of Easter today follows the same. Accordingly, churches in the West observe it on the first day of the full moon that occurs on or following the Spring equinox on March 21., it became a movable feast between March 21 and April 25.
Still some churches in the East observe Easter according to the date of the Passover festival.
The preparation takes off as early as on the Ash Wednesday from which the period of penitence in the Lent begins. The Lent and the Holy week end on the Easter Sunday, the day of resurrection.