The Revised Julian calendar is the calendar that was adopted by the Eastern Orthdox church in 1923, to replace the Julian calendar. It uses a different rule for the leap year than the Gregorian calendar, used by the rest of Christianity and by the world in general for secular purposes. In the Gregorian calendar, leap years occur in centuries only if the year is divisible by four hundred. In the Revised Julian calendar, leap years occur in centuries only if the year divided by nine hundred gives a remainder of two hundred or six hundred. The two calendars are identical for all years from 1601 until 2799. In the year 2800, a leap year will occur in the Gregorian calendar, without a leap year occurring in the Revised Julian calendar.
