Kyriopascha

Kyriopascha is the rare concurrence of the Great Feast of the Annunciation (March 25) with Pascha. It is an especially festive event, including complex rubrics for its liturgical celebration.

Because of the difference between the astronomical vernal equinox and the theoretical vernal equinox calculated by the Julian Calendar—the latter of which is used by both the Julian Calendar and the Revised Julian Calendar to calculate Pascha—Kyriopascha never occurs on the Revised Julian Calendar, while it can occur on the Julian. It can also occur on the Gregorian Calendar, however, which uses the astronomical vernal equinox to calculate the date of Pascha. As such, Kyriopascha can be celebrated by the Old Calendar churches and those New Calendar churches which use the Gregorian Calendar (i.e., Finland and Estonia), though it will not occur in the same year.

The last Kyriopascha on the Julian calendar was in 1991, and the next will be in 2075, 2086 and 2159. The last Kyriopascha on the Gregorian Calendar was in 1951, and the next will be in 2035, 2046 and 2103.