typikon/docs/calendars.md

The state of the calendars

Which churches keep which reckoning, and what this program models of each.

Three independent questions

Almost every disagreement about the date of a feast comes from conflating these. They vary separately.

The paschalion decides Pascha and everything counted from it: the Triodion, Great Week, the Pentecostarion, the Apostles' Fast. Two tables are in use. The Julian Paschalion is the old computus, worked in the Julian calendar and read onto a civil date. The Gregorian Paschalion is the Western one. They agree in some years and can diverge by five weeks.

The menologion decides the fixed feasts: the Nativity, Theophany, the Dormition, and every saint's day. Two calendars are in use. The Julian menologion runs thirteen days behind the civil calendar until 2100 and fourteen after it. The Revised Julian menologion agrees with the Gregorian for every date until 2800, so in practice it is the civil calendar.

The usage decides rank and some of the fast: Greek books and Slavic books read the same Typikon a little differently.

The three combinations in use have short names:

	paschalion	menologion	kept by
old	Julian	Julian	Moscow, ROCOR, Serbia, Georgia, Jerusalem, the Holy Mountain, Poland, Macedonia, ACROD
new	Julian	Revised Julian	Constantinople, Greece, Antioch, the OCA, Romania, Bulgaria, Cyprus, Albania, Ukraine
western	Gregorian	Revised Julian	the Finnish Orthodox Church; most Byzantine Catholic churches

A new-calendar church therefore keeps the Nativity with the West and Pascha with the East. That is not a compromise but what the 1923 congress at Constantinople decided: adopt the Revised Julian menologion, leave the paschalion alone.

How it came about

The Pan-Orthodox Congress of May 1923 proposed the Revised Julian calendar. Constantinople, Greece, Romania, Poland and others adopted it over the following years; Alexandria, Antioch, Bulgaria and Cyprus followed later. Jerusalem, Russia, Serbia, Georgia and the Holy Mountain did not, and have not.

Three changes since are worth knowing because they are recent enough to catch out a printed reference:

• 1923. The Council of Bishops of the Russian Church Abroad rejected the new calendar outright, which is why ROCOR is Julian throughout and why that became part of its identity rather than a regional custom.
• 2014. The Polish Orthodox Church returned to the Julian menologion after decades on the Revised Julian. Some parishes kept the new calendar.
• 1 September 2023. The Ukrainian Greek Catholic Church and the Orthodox Church of Ukraine moved their fixed feasts to the Revised Julian calendar, keeping the Julian Paschalion.

One Orthodox church keeps the Gregorian Paschalion: the Finnish Orthodox Church, which has done so since the 1920s.

The Orthodox churches

All twenty are modelled, with the Typikon's own discipline. The Orthodox Church legislates fasting as tradition rather than as precept, so nothing is reported as binding for any of them.

jurisdiction	reckoning	usage
moscow rocor serbian georgian jerusalem athos polish macedonian acrod	old	Slavic, except georgian jerusalem athos
constantinople goarch greece antiochian cyprus albanian romanian	new	Greek
oca bulgarian ukrainian	new	Slavic
finnish	western	Greek

Where a church is not uniform, the jurisdiction's note says so: most OCA parishes keep the new calendar and a minority of Carpatho-Russian and Alaskan background keep the old; ACROD publishes both cycles and its parishes keep one or the other; Polish parishes vary since 2014.

The Byzantine Catholic churches

Fourteen Eastern Catholic churches use the Byzantine rite. Four have entries.

church	reckoning	particular law on fasting
ruthenian, the Metropolia of Pittsburgh	western	modelled, from the Metropolia's own published rule
ugcc, Ukrainian Greek Catholic	new since 2023	its own; not modelled
melkite, Melkite Greek Catholic	western	its own; not modelled
romanian-catholic, Romanian Greek Catholic	western	its own; not modelled

The other ten are the Slovak, Hungarian, Križevci (Croatia and Serbia), Italo-Albanian, Greek, Bulgarian, Macedonian, Belarusian, Russian and Albanian Greek Catholic churches. They have no entry because their reckonings are not uniform and are not recorded in general reference: several vary by eparchy, and the churches that sit beside a local Orthodox majority often keep that majority's paschalion for the sake of a common Pascha, as Melkite parishes in the Middle East do.

Any of them keeps one of the three reckonings above, and two questions decide which:

1. Is Pascha kept with Rome, or with the local Orthodox?
2. Are the fixed feasts on the civil calendar, or thirteen days behind it?

with Rome	civil calendar	--calendar western
with the local Orthodox	civil calendar	--calendar new
with the local Orthodox	thirteen days behind	--calendar old

Add --tradition slavic or --tradition greek for the usage the books follow. A patch adding a church, with a source for its calendar, is welcome.

Why the law is never borrowed

Every Eastern Catholic church legislates its own fasting discipline, and they differ. Ruthenian particular law binds on four kinds of day in the year: strict abstinence on the first day of the Great Fast and on Great and Holy Friday, and abstinence from meat on the Wednesdays and Fridays of the Great Fast. That is the Metropolia of Pittsburgh's law and is reported for that church alone.

The others are shown at the Typikon's discipline with nothing reported as binding. Telling a Melkite that fourteen days a year oblige him under a law written for Pittsburgh would be a false statement about his obligations, which is a worse failure than saying nothing. When a church's law is sourced, its entry will carry it.

--typikon shows any of these churches at the full Byzantine discipline while still reporting whatever its own law obliges. For a Byzantine Catholic that is usually the flag you want: the law is the floor, not the fast.

Not in scope

Nine Eastern Catholic churches do not use the Byzantine rite: the Maronite, Chaldean, Syro-Malabar, Syro-Malankara, Syriac, Armenian, Coptic, Ethiopian and Eritrean churches. They have their own rites, their own sanctorals and their own fasting structures, and none of the machinery here applies to them: there is no Triodion, no Pentecostarion, no Byzantine menologion. The Latin Church likewise.

Supporting any of them would be a different program sharing nothing but the word "calendar".