Julian calendar
Modern usage
Although most Eastern Orthodox countries (most of them in eastern or southeastern Europe) had adopted the Gregorian calendar by 1924, their national churches had not. The "Revised Julian calendar" was endorsed by a synod in Constantinople in May 1923, consisting of a solar part which was and will be identical to the Gregorian calendar until the year 2800, and a lunar part which calculated Easter astronomically at Jerusalem. All Orthodox churches refused to accept the lunar part, so all Orthodox churches continue to celebrate Easter according to the Julian calendar, with the exception of the Finnish Orthodox Church, which uses the Gregorian Paschalion.
Julian calendar-82