On Kyriopascha, the polyeleos normally appointed for the Annunciation is omitted, the canon of Annunciation is sung together with the Paschal canon during Orthros, and the Gospel of the Annunciation is read after the sixth ode of the canon. On the remaining days of Bright Week the usual Paschal services for these days are performed in combination with the service for the Annunciation: the litia and artoklasia at Vespers, and the polyeleos, megalynarion, and Gospel reading at Orthros.
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 elimination of Kyriopascha from the cycle of the Revised Julian Calendar is one of the criticisms leveled against those who use that reckoning.
One of the more notable celebrations of Kyriopascha in history was in 1821, the day which also marked the uprising of the Greeks against the Ottoman Turks, leading to Greek independence.
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.
- Liturgical Havoc Wreaked by the "New Julian" Calendar, by Hieromonk Cassian