Orthodox Easter Date Differs From Western Churches
Why this is here: The divergence in Easter dates is due to a 13-day difference between the Julian and Gregorian calendars, with the Julian calendar starting the new year on January 13.
Orthodox Christians celebrate Easter on April 12, later than Western churches. The date for Easter was first determined in 325 AD at the Council of Nicaea. It stipulated Easter falls on the Sunday after the first spring full moon.
Orthodox Christians typically do not celebrate on the same day as Catholics and Protestants. An exception will occur in 2025, when both groups observe Easter on April 20.
This difference stems from the calendars used. Western churches follow the Gregorian calendar, while Orthodox churches use the Julian calendar.
The Julian calendar, established by Julius Caesar, differs from the Gregorian calendar by 13 days. The Julian calendar begins the new year on January 13, causing a shift in the dates of religious holidays. This also affects Easter, as the spring equinox falls later in the Julian calendar.