Revised Julian calendar

The Revised Julian calendar, or less formally the new calendar and also known as the Milanković calendar, is a calendar proposed in 1923 by the Serbian scientist Milutin Milanković as a more accurate alternative to both Julian and Gregorian calendars. At the time, the Julian calendar was still in use by all of the Eastern Orthodox Churches and affiliated nations, while the Catholic and Protestant nations were using the Gregorian calendar. Thus, Milanković's aim was to discontinue the divergence between the naming of dates in Eastern and Western churches and nations. It was intended to replace the Julian calendar in Eastern Orthodox Churches and nations. From 1 March 1600 through 28 February 2800, the Revised Julian calendar aligns its dates with the Gregorian calendar, which had been proclaimed in 1582 by Pope Gregory XIII.^[1]

The Revised Julian calendar has been adopted for ecclesiastical use by the Ecumenical Patriarchate of Constantinople, the Orthodox Autocephalous Church of Albania, the Greek Orthodox Church of Alexandria, the Greek Orthodox Church of Antioch, the Bulgarian Orthodox Church, the Romanian Orthodox Church, the Cypriot Orthodox Church, the Church of Greece, the Orthodox Church of the Czech Lands and Slovakia, the Orthodox Church in America,^[2] the Orthodox Church of Ukraine, the Orthodox Church in Japan,^[3][4] and the Eastern Catholic Ukrainian Greek Catholic Church. It has not been adopted by the Russian Orthodox Church, the Serbian Orthodox Church, the Macedonian Orthodox Church, the Georgian Orthodox Church, the Polish Orthodox Church and the Greek Orthodox Patriarchate of Jerusalem. It has not been adopted by any nation as an official calendar. Instead, all of the Eastern Orthodox nations have adopted the Gregorian calendar as the official state calendar.

The Revised Julian calendar has the same months and month lengths as the Julian and Gregorian calendar, but, in the Revised Julian version, years evenly divisible by 100 are not leap years, except that years with remainders of 200 or 600 when divided by 900 remain leap years, e.g. 2000 and 2400 as in the Gregorian calendar.^[5]