An excellent post by my friend John Morgan, on the subject of Easter, its origins, calculations, etc.
One still gets those who say that it is borrowed from Paganism, and while it seems reasonably certain that the English / Germanic name for this holiday was adopted via a month-name (“Ēastermōnaþ” and variations on the linguistic theme) from Eostre (reconstructed OHG *Ostara), a purported goddess who – interestingly enough – is attested only in the works of St. Bede the Venerable, the Anglo-Saxon Christian proto-historian (!), and while there has clearly been some borrowing / adoption / adaption of existing European folk traditions as Christianity moved out of its original Mediterranean context and into Western and Northern Europe, associating Easter with goddesses like Ishtar and Astarte is… well, let’s just be gentle, and say it’s a stretch. 🙂
Historically, as John points out, the dating of Easter is based on the dating of the Jewish feast of Passover; the only parallel with European Paganism is that both had Spring feasts in the vicinity of the Vernal Equinox, and/or the Full Moon nearest to it. There is nothing surprising about such parallels, and it doesn’t imply a connection, other than a basic human one.
Similarly, for the early Christian evangelists of Anglo-Saxon England to find parallels between a month dedicated to the dawn, rising sun, increasing light, etc., and Jesus, who was known as the Day-Star, compared to the Dayspring (dawn), hailed as the Sun of Righteousness, and called by the Gospel-writer St. John the “light [which] shines in the darkness, and the darkness has not overcome it,” is hardly surprising!
Theologically, of course, there are considerable differences between the Christian message and the Pagan myths which preceded it. Christians – myself included – would point out that these were prefigurings, foreshadowings, of the “true myth” (C.S. Lewis) which is Christianity; the “dying god” of Paganism being a shadow of the form (to put it in Platonic terms) which was embodied and given geographical and historical, and of course human, context in Jesus of Nazareth: the Incarnate Word of God. For more on this, see my reflections on “Christianity in an Age of Unbelief,” posted earlier.