The observance of the feast of Passover extends back to the time when the children of Israel were commanded to obey it as part of their delivery from Egyptian captivity. The festival, beginning on Nisan 14 (modern March-April) with the sacrifice of the lambs, lasted for seven days. The celebration of the Passover-the event also known as the Last Supper in the synoptic Gospels-began with the sacrifice of the paschal lambs in the temple, portions of which were to be eaten as part of the Passover meal. According to the Gospels, Jesus Christ died on the Friday of Passover week and was resurrected on the first day of the week (Sunday) during the festival (Matthew 27-28:1). Therefore, the celebration of Easter traditionally fell in Western Christian churches on the first Sunday after the start of the Passover feast.
This simple solution, however, is fraught with difficulties. The month of the Passover feast was to begin with the new moon-determined in the first century by sight only-after the vernal equinox (which in the first century was March 21 for Jews, March 25 for the Romans). If the new moon was sighted correctly, then the night of Passover was a full moon. Because weather patterns are not always static, the new moon might not be observed on the exact night on which it occurred, leading to errors for the starting date of Passover. Moreover, many Jews of the first century followed a lunar calendar and roughly every three years found it necessary to intercalate (or insert) an entire month prior to the start of Nisan. The intercalation of another lunar month (29.5 days) would push the Passover further into April.
For the first two or three centuries, Christians were reliant upon the announcement of the Jewish Passover to calculate when to celebrate Easter. In the third and early fourth centuries (particularly at Nicea in A.D. 325), Christians developed their own method of calculating Easter dates based on Alexandrian astronomical calculations for the duration of the solar year. Today, Easter no longer represents the Sunday after the start of the Jewish Passover but instead represents a more accurate calculation of the date.
Living out a great season of my life, thanks to Jesus Christ, and two wonderful daughters, a great life's work. Loving this opportunity to share faith online... I'm a single Mom, convert to The Church of Jesus Christ of Latter-day Saints, second-gen Italian, from the East coast originally. Love the fine arts, dance, frozen yogurt, temples, scriptures, writing, jazz, helping others reach their potential, king salmon, ....and not in that order. God is good. I feel it deeply when people have a misconception of Heavenly Father or Jesus Christ, His Son, that lessens or cheapens Them and blinds one's ability to feel His presence or to trust in an ultimately good eternal end to life's circumstances.