The Revised Julian Calendar and Its Reception

Milutin Milanković’s scheme is astronomically the most accurate calendar in ecclesiastical use, and the churches that adopted it deliberately left the Paschalion untouched so that all Orthodox would keep Pascha together. But pairing a Gregorian-aligned fixed calendar with the Julian Paschalion has one concrete and checkable liturgical consequence: it shortens the Apostles’ Fast by thirteen days every year and, when Pascha is late, abolishes it. This file sets out the scheme, its adoption church by church, and that anomaly with worked examples.

Tradition: Pan-Orthodox

The Scheme

Milutin Milanković (1879–1958), the Serbian astronomer and climatologist, attended the 1923 Congress as a technical delegate. His proposal, refining an earlier suggestion by Maksim Trpković, kept the ordinary four-year leap rule and altered only the treatment of century years:

A year divisible by 4 is a leap year, except that a year divisible by 100 is a leap year only if, divided by 900, it leaves a remainder of 200 or 600.

The arithmetic: in any 900 years there are 225 leap years by the four-year rule, less the 9 century years, plus the 2 century years that survive the test — 218 leap days per 900 years. The mean year is therefore 365 + 218/900 = 365.242222 days, against the Gregorian 365.2425 and the mean tropical year of about 365.2422. The Revised Julian calendar is more accurate than the Gregorian, and this should be conceded without hesitation by anyone arguing on the other side.

Because 2000 leaves remainder 200 and 2400 leaves remainder 600, both are leap years in both systems; 2100, 2200, 2300 are leap years in neither. The two calendars first diverge in 2800, a Gregorian leap year and a Revised Julian common year. Until then “Revised Julian” and “Gregorian” name the same dates, which is why the popular usage that treats them as interchangeable is practically harmless and technically wrong.

The Congress specified that the thirteen-day correction take effect on 1 October 1923, to be numbered 14 October (see The Congress of 1923 and What It Proposed).

What the Scheme Deliberately Left Alone

The Revised Julian calendar governs the fixed calendar only. The Paschalion was not altered. Pascha and the whole movable cycle continue to be computed by the received Alexandrian reckoning on Julian dates and then expressed civilly, exactly as before (see The Drift and What It Does and Does Not Affect).

This was a deliberate act of restraint and it deserves to be said plainly. The Congress had before it a more thorough proposal — computing Pascha astronomically at the meridian of Jerusalem — and declined it. Had it been adopted, Orthodoxy would have divided at the one point where it is genuinely and universally united. The reformers changed the less dangerous system. Whatever else is said in this collection about 1923, that judgment was sound.

The cost of the restraint is the subject of the rest of this file.

Adoption, Church by Church

Adoption was piecemeal, and each church acted by its own synod rather than under the Congress’s authority.

Church of Greece — by encyclical of the Holy Synod, March 1924: 10 March 1924 was renamed and kept as 23 March 1924. The Churches of Constantinople and Cyprus changed at the same time.
Romania — 1924.
Poland — 1924, by synodal decision of 12 April 1924; reversed in 2014 (see below).
Alexandria — 1928, under Patriarch Meletios II, the same Meletios (Metaxakis) who had convened the Congress as Ecumenical Patriarch.
Antioch — Antioch had rejected the 1923 proposal and did not attend the Congress; it adopted the new calendar for fixed feasts later, the standard accounts dating the change to the 1940s (see Orthodoxy: The Church Calendar, which states the point with the same caution).
Bulgaria — by decision of the Holy Synod of July 1968, effective 20 December 1968. [Disputed: the December 1968 date is given by the Bulgarian News Agency and is reflected in the record of the subsequent litigation over the Bulgarian Old Calendar body (Bulgarian Orthodox Old Calendar Church and Others v. Bulgaria, European Court of Human Rights, application no. 56751/13); some reference works instead give 1963 (“Revised Julian calendar,” Wikipedia, locator per METHODOLOGY §2.3). This collection follows the 1968 dating, which agrees with Orthodoxy: Calendar and Typikon in ROCOR.]
Poland, again — on 18 March 2014 the Synod of Bishops of the Polish Autocephalous Orthodox Church revoked its own decision of 1924 and returned to the Julian calendar with effect from 15 June 2014, allowing parishes that wished to keep the new calendar to do so (“An unprecedented decision: the Polish Orthodox Church is returning to the old calendar,” OrthoChristian.com, locator). It is the only church to have reversed the change.
Orthodox Church of Ukraine — on 1 September 2023, following approval by its Local Council of 27 July 2023, with parishes and monasteries permitted to retain the Julian calendar by decision of the parish assembly (Orthodox Times, orthodoxtimes.com, locator). This is recent and is reported here as a calendrical fact only; the ecclesiological questions surrounding the OCU are not treated in this collection and are handled elsewhere in the repository (see Orthodoxy: World Orthodoxy).

Retaining the Julian calendar throughout: Jerusalem, Russia (including ROCOR), Serbia, Georgia, Mount Athos, Sinai (see The Current Map for the position as of August 2026).

The Orthodox Church of Finland is a separate case: it adopted not the Revised Julian scheme but the Gregorian calendar entire, including the Gregorian Paschalion, in the early 1920s, and remains the only Orthodox church to keep Pascha with the West.

The Apostles’ Fast Anomaly

This is the one concrete, arithmetically demonstrable liturgical defect of the mixed arrangement, and it is worth setting out slowly.

The structure. The Apostles’ Fast begins on the Monday after All Saints Sunday — All Saints being the eighth Sunday after Pascha, so the Monday is the fifty-seventh day after Pascha — and ends on 28 June, the eve of Ss Peter and Paul (see Orthodoxy: Fasting Periods; The Fixed and the Movable Year). Its start is governed by the Paschalion; its end by the Menaion.

The effect. Move the Menaion thirteen days earlier and leave the Paschalion alone, and the fast’s end moves thirteen days earlier while its start does not move at all. The fast is thirteen days shorter, every single year. And when Pascha is late enough, the end arrives before the start.

The threshold. The fast survives on the Revised Julian calendar only if the Monday after All Saints falls on or before 28 June — that is, only if Pascha falls on or before 2 May. Orthodox Pascha ranges from 4 April to 8 May in civil dates. In every year in which Pascha falls after 2 May, a New Calendar church has no Apostles’ Fast at all.

Worked examples.

Year	Pascha (civil)	Fast begins (Mon. after All Saints)	Old Calendar: fast ends (28 June Julian = civil)	Old Calendar length	New Calendar: fast ends (28 June civil)	New Calendar length
2025	20 April	16 June	11 July	26 days	28 June	13 days
2024	5 May	1 July	11 July	11 days	28 June — already past	none
2013	5 May	1 July	11 July	11 days	28 June — already past	none

The 2024 and 2013 rows are not hypotheticals. In those years an Orthodox Christian on the Revised Julian calendar kept no Apostles’ Fast, because the feast the fast prepares for had already been celebrated before the fast could begin. The point is made in the same terms by the Sretensky Monastery’s published answer to the question, and by other Orthodox commentators on both calendars (“Can the Apostles Fast Ever Be Skipped by Those Using the New Calendar or Old Calendar?”, Sretensky Monastery Q&A, Pravoslavie.ru / OrthoChristian.com; and see Orthodoxy: Calendar and Typikon in ROCOR, which states it in the same way).

What this is and is not evidence for. It is evidence that the mixed calendar produces a real liturgical defect, that the defect was not intended, and that it recurs on a predictable schedule. It is not evidence that New Calendar churches have abandoned fasting: jurisdictions on the new calendar are aware of the problem and give their own pastoral direction, and the Apostles’ Fast is in any case the most variable and the mildest of the four fasts (see The Fasting Seasons and Their Logic). The argument built on it is made at The Case for the Old Calendar, and the reply to it — which is a real reply and not a dodge — at The Case on the Other Side.

The Reception: Division

The change was not received quietly. Popular resistance in Greece began immediately and hardened into separation; Romania and Bulgaria produced their own Old Calendarist bodies; Cyprus had its dissenters. That history — the persons, the dates, the fragmentations, and where this library stands in relation to it — is treated at The Old Calendarist Separations, and is not anticipated here.

One summary judgment belongs in this file, because it is a judgment about the reform rather than about the dissenters. A calendar exists so that a community may keep its feasts together. The reform of the 1920s was undertaken partly for the sake of unity — with the surrounding society, and in some accounts with other Christians — and its immediate effect was that Orthodox Christians in the same country, and eventually on the same street, ceased to keep the Nativity on the same day. Whatever the merits of the Revised Julian calendar as an instrument, its introduction did not produce the unity it was meant to serve.

References

“Can the Apostles Fast Ever Be Skipped by Those Using the New Calendar or Old Calendar?” Sretensky Monastery Q&A. Pravoslavie.ru / OrthoChristian.com.
Bulgarian Orthodox Old Calendar Church and Others v. Bulgaria. European Court of Human Rights, application no. 56751/13.
“An unprecedented decision: the Polish Orthodox Church is returning to the old calendar.” OrthoChristian.com (locator).
“Orthodox Church of Ukraine changes calendar.” Orthodox Times, orthodoxtimes.com (locator).
“Revised Julian calendar”; “Council of Constantinople (1923).” Wikipedia (locators per METHODOLOGY §2.3).
Viscuso, Patrick, ed. and trans. A Quest for Reform of the Orthodox Church: The 1923 Pan-Orthodox Congress. Berkeley: InterOrthodox Press, 2006.
Ware, Timothy (Kallistos). The Orthodox Church. Rev. ed. London: Penguin, 1993.