Why celebrate The Resurrection on different days?

The Christian Easter date is established upon a rule which was set within the Ecumenical Synod I, in 325: Easter is in the first Sunday after full moon that follows spring equinox.

All Christian churches respect this rule.

The Orthodox Church respects also another rule: if the Christian Easter date is concomitant with the Jewish Easter, the Resurrection is moved the next Sunday.

So, there are considered two astronomical phenomena: a fixed one –the equinox and a variable one –full moon.

The gap time between the Catholic Easter and the Orthodox one in some years is caused, though, by the difference between the two calendars which are considered regarding the calculation of this date.

The Orthodox churches take into account the old calendar when it comes to settle the Easter date, while the Roman-Catholic, Protestant and Evangelical churches follow the new calendar.

The 13-day time difference between these calendars determines also the spring equinox to be delayed with 13 days from a calendar to another.

The full moon is an obvious criterion, irrespective of calendar, because it is visible on the sky.

Its closer or farther appearance from the spring equinox ,therefore influences overlaping or delaying of Easter date.

The one-week difference between the Catholic and Orthodox Easter in 2012 is not caused by the full moon appearance, but the coincidence with the Jewish Easter.

The Sunday after full moon, which follows the spring equinox this year is in the second day of Jewish Easter, so the Orthodox Church celebrates the Resurrection one week later.

The year when all Christians will celebrate Easter on the same date is 2014.

The Easter date for the next 10 years:

Translated by Alexandra-Diana Mircea
MTTLC, Bucharest University