Here's some interesting facts about Easter from H.B. London.
We all know that Christmas falls on December 25 and that our Independence Day celebration always takes place on July 4, but why do we observe Easter anytime from March 22 to April 25, and why is Easter usually after Passover, but sometimes before? And, to add to the confusion, for over a thousand years, the Western Church and the Eastern Orthodox Church have seldom celebrated Easter on the same day.
While both branches of the church calculate Easter as the first Sunday after the first full moon — on or after the Vernal Equinox (first day of Spring) — the Eastern Orthodox Church bases the calculation on the Julian calendar, while the Western Church uses the Gregorian calendar. The date of Passover (Pesach in Hebrew) is not based on the Julian or the Gregorian, but on the Jewish calendar, which places the beginning of Passover on the 15th day of the month of Nisan. As a result of the differences in the rules between the Hebrew and Gregorian cycles, Passover falls about a month after Easter in three years of the 19-year cycle.
Because of the changing date for the observance of Easter, some Christians feel that, for the sake of unity within the church around the world, the celebration of the resurrection of Christ should take place on the same day each year — such as the second Sunday of April. In 1963, the Second Vatican Council agreed that Easter should become a fixed holiday and, in 1997, the National Council of Churches proposed that the Western and Eastern churches find a unified method of calculating the date of Easter. This year and next, Easter just happens to be celebrated on the same day in both the Western and Eastern Church, but that is not scheduled to take place again until 2014 and 2017.
