In the early days of the Roman Catholic Church, many disputes arose as to fixing a proper date for the celebration of the Easter feast. To finally end all arguments, the first Holy Roman Catholic Emperor Constantine the First, decreed that a council be held in 325 AD at Nicea (Iznik, Turkey). Here the Bishops decided that Easter be celebrated on the first Sunday after the full moon following the spring equinox, with a proviso that should this correspond with the Jewish feast of the Passover, then Easter would fall on the following Sunday.

It finally settled the debate, but then a discrepancy arose between the astronomical year and the Julian calendar used then. This kept on widening until Pope Gregory XIII introduced the Gregorian calendar in 1582 AD. All the Western churches finally accepted this, except the Eastern ones. They still have their own method to determine when Easter is celebrated.

In the early 20th century a move was made to have the Easter date permanently fixed like the Christmas feast. In 1923, the Vatican announced that they could find no canonical objection to this suggestion. Because of objections from certain countries that could not agree to this. The idea was eventually dropped. Today the Easter feast is a moveable date.

The earliest it can be celebrated is March 22nd. The last time it occurred then was in 1818 and the next time it falls on that date will be 2285. The latest date it can possibly fall on is April 25th. It last happened in 1943 and will not occur again until 2083. This year the Easter feast will fall on March 27th.