Easter,^{[nb 1]} also called Pascha^{[nb 2]} (Aramaic, Greek, Latin) or Resurrection Sunday,^{[nb 3]} is a Christian festival and cultural holiday commemorating the resurrection of Jesus from the dead, described in the New Testament as having occurred on the third day of his burial following his crucifixion by the Romans at Calvary c. 30 AD.^[12][13] It is the culmination of the Passion of Jesus Christ, preceded by Lent (or Great Lent), a 40-day period of fasting, prayer, and penance.

Easter and its related holidays are moveable feasts, not falling on a fixed date; its date is computed based on a lunisolar calendar (solar year plus Moon phase) similar to the Hebrew calendar. The First Council of Nicaea (325) established only two rules, namely independence from the Hebrew calendar and worldwide uniformity. No details for the computation were specified; these were worked out in practice, a process that took centuries and generated a number of controversies. It has come to be the first Sunday after the ecclesiastical full moon that occurs on or soonest after 21 March.^[18] Even if calculated on the basis of the more accurate Gregorian calendar, the date of that full moon sometimes differs from that of the astronomical first full moon after the March equinox.^[19]

The earliest date on which [Western] Easter Sunday can occur is March 22. This was the case in the year 1818, and it will not happen again until the year 2285.

The latest date it can fall on is April 25. The last time Easter Sunday fell on April 25 was in 1943, and the next occurrence will be in 2038.

[From Wikipedia]