Editing Julian calendar (section)

== Modern usage ==
=== Eastern Orthodox ===
{{See also|New Calendarists}}[[File:Bogojavlenie.jpg|thumb|250px|[[Russian icon]] of the [[Epiphany (feast)|Theophany]] (the baptism of Jesus by [[John the Baptist]]) (6 January), the highest-ranked feast which occurs on the fixed cycle of the [[Eastern Orthodox liturgical calendar]]]]

Although most [[Eastern Orthodox Church|Eastern Orthodox]] countries (most of them in [[Eastern Europe|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 Eastern 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]]<ref>Bishop Photius of Triaditsa, [http://orthodoxinfo.com/ecumenism/photii_2.aspx "The 70th Anniversary of the Pan-Orthodox Congress, Part II of II"]; {{cite web
|url=http://www.hs.fi/english/article/Moscow-affiliated+Russian+Orthodox+church+grows+in+Helsinki/1135230488329
|date=21 September 2007
|title=HELSINGIN SANOMAT (International edition)
|access-date=11 May 2010
|archive-date=14 July 2014
|archive-url=https://web.archive.org/web/20140714150231/http://www.hs.fi/english/article/Moscow-affiliated+Russian+Orthodox+church+grows+in+Helsinki/1135230488329
|url-status=dead
}}</ref> and the [[Estonian Apostolic Orthodox Church|Estonian Orthodox Church]].<ref>{{cite thesis |title=THE DATE OF EASTER: CLASSICAL CONSIDERATIONS AND CONTEMPORARY CHALLENGES |date=2024 |url=https://ruor.uottawa.ca/server/api/core/bitstreams/300383f1-5612-4680-b15a-d4112434713c/content |first=R.D. ALBERT P. |last=MARCELLO  |pages=135, 136 |publisher=University of Ottawa}}</ref>).

The Orthodox Churches of [[Eastern Orthodox Patriarchate of Jerusalem|Jerusalem]], [[Russian Orthodox Church|Russia]], [[Serbian Orthodox Church|Serbia]], [[Montenegrin Orthodox Church|Montenegro]], Poland (from 15 June 2014), [[Macedonian Orthodox Church – Ohrid Archbishopric|North Macedonia]], [[Georgian Orthodox and Apostolic Church|Georgia]], and the [[Greek Old Calendarists]] and other groups continue to use the Julian calendar, thus they celebrate the Nativity on 25 December ''Julian'' (which is 7 January ''Gregorian'' until 2100). 

The [[Orthodox Church of Ukraine]] announced in late May 2023 that they would use the Gregorian calendar to celebrate Christmas on December 25, 2023, partly in reflection to [[Russia]]'s [[Russian invasion of Ukraine|invasion of the country]] in early 2022; the church continues to celebrate Easter on the date according to the Julian tradition.<ref>{{cite news |title=Orthodox Church of Ukraine to switch to Revised Julian calendar, celebrate Christmas on Dec. 25 |date=May 24, 2023 |url=https://kyivindependent.com/orthodox-church-of-ukraine-to-switch-to-revised-julian-calendar-celebrate-christmas-on-dec-25/ |work=Kyiv Independent }}</ref>

==== Date of Easter ====
Most branches of the [[Eastern Orthodox Church]] use the Julian calendar for [[Computus|calculating the date of Easter]], upon which the timing of all the other [[moveable feast]]s depends. Some such churches have adopted the [[Revised Julian calendar]] for the observance of [[fixed feast]]s, while such Orthodox churches retain the Julian calendar for all purposes.<ref>[http://www.oikoumene.org/en/resources/documents/commissions/faith-and-order/i-unity-the-church-and-its-mission/towards-a-common-date-for-easter/index Towards a Common Date of Easter.] {{Webarchive|url=https://web.archive.org/web/20170620205601/http://www.oikoumene.org/en/resources/documents/commissions/faith-and-order/i-unity-the-church-and-its-mission/towards-a-common-date-for-easter/index |date=2017-06-20 }} (5–10 March). World Council of Churches/Middle East Council of Churches Consultation, Aleppo, Syria.</ref>

===Syriac Christianity===
The [[Ancient Assyrian Church of the East]], an [[East Syriac]] rite that is commonly miscategorised under "eastern Orthodox", uses the Julian calendar, where its participants celebrate Christmas on 7 January ''Gregorian'' (which is 25 December ''Julian''). The [[Assyrian Church of the East]], the church it split from in 1968 (the replacement of traditional Julian calendar with Gregorian calendar being among the reasons), uses the Gregorian calendar ever since the year of the [[schism]].<ref>[https://theorthodoxchurch.info/blog/news/the-quest-for-orthodox-assyrian-alliance/ The Quest for Orthodox–Assyrian Alliance] {{Webarchive|url=https://web.archive.org/web/20210502080754/https://theorthodoxchurch.info/blog/news/the-quest-for-orthodox-assyrian-alliance/ |date=2021-05-02 }} Orthodoxy Cognate PAGE</ref>

=== Oriental Orthodox ===
The [[Armenian Patriarchate of Jerusalem]] of [[Armenian Apostolic Orthodox Church]] uses Julian calendar, while the rest of Armenian Church uses Gregorian calendar. Both celebrate the Nativity as part of the Feast of [[Epiphany (holiday)|Theophany]] according to their respective calendar.<ref>{{Cite web|url=https://www.peopleofar.com/2015/01/07/armenians-celebrate-christmas-january-6th/|title=Armenian Christmas on January 6th|last=Reply|first=hairabed|date=2015-01-07|website=PeopleOfAr|language=en-US|access-date=2018-12-21}}</ref>

=== Berbers ===
The Julian calendar is still used by the [[Berbers]] of the [[Maghreb]] in the form of the [[Berber calendar]].<ref>{{cite journal|title=The manipulation of time: Calendars and power in the Sahara|first=Clare|last=Oxby|journal=Nomadic Peoples |series=New Series|volume=2|issue=1/2|year=1998|pages=137–149|doi=10.3167/082279498782384522|jstor=43123542}}</ref>

=== Foula ===
[[Foula]] in [[Shetland]], [[Scotland]], a small settlement on a remote island of the archipelago, still celebrates festivities according to the Julian calendar.<ref>{{cite news |last1=Merritt |first1=Mike |title=Remote Foula islanders finally get to celebrate Christmas |url=https://www.thetimes.com/uk/scotland/article/remote-foula-islanders-finally-get-to-celebrate-christmas-lcjlrn56m |date=27 December 2023 |language=en}}</ref>