Calendar reform

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The change in the division and counting of periods is called calendar reform . Many calendar reforms arose from the societal need for greater precision in planning the sowing in agriculture. In addition, there are also purely politically or religiously motivated calendar reforms.

The most important reforms of the first kind are the calendar reform of Julius Caesar 46 BC. BC, whose switching rule was only enforced by Augustus in the year 8 AD , and the correction of the calendar with a correction of the leap year regulations by the Gregorian calendar in 1582. The introduction of the Christian year counting (in 525 by Dionysius Exiguus ), however, is not considered a calendar reform in the narrower sense.

Calendar correction by Augustus

While the Julian calendar fixed the position of the seasons in the calendar, it was only Augustus who enforced the correct application of the switching rule for fine adjustment. Because the Julian switching rule ("quarto quoque anno") in the time after Caesar's death, after 44 BC. When applied incorrectly, the calendar shifted from the astronomical turning point of the earth's orbit around the sun (solstices and equinoxes). Augustus corrected this in the year 8. Until then, the priesthood had counted the starting year (" inclusive count ") with the switching rule "every fourth year" - customary at the time - so that (according to today's "exclusive count") already in each A leap day was inserted in the third year.

There was therefore no calendar reform in the narrower sense through Augustus. The widespread legend that Augustus renamed "his" month out of vanity and extended it and that other months were also extended or shortened was first invented by Johannes de Sacrobosco in the 13th century. In fact, as early as 45 BC. The months ianuarius, martius, maius, quintilis , sextilis , octobris and decembris 31 days.

Gregorian calendar reform

According to Pope Gregory XIII. The Gregorian calendar reform in 1582 essentially had the effect that the current calendar date “21. March “coincides again with the astronomical event of the primary equinox (spring-day-night equinox of the northern hemisphere). Because the leap day rule of the Julian calendar was applied schematically after the Augustan correction, the calendar and with it the current date “21. March ”was postponed by ten days over the centuries until 1582. The restoration of the astronomical and calendar relationships that existed during the Council of Nicea in 325 in 1583 was brought about within the framework of the papal bull Inter gravissimas by the fact that in 1582 the daily counting of the calendar included between October 4th and October 15th lying counting days were omitted. In the calendar of the year 1582, Thursday, October 4th, followed Friday, October 15th. In the following year, a glance at the daily calendar on the day of the astronomical event Primary Equinox - as in 325 - again showed March 21st. In order to avoid a further shifting of the calendar date away from the day of the primary equinox, the reform rule finally determined that those secular years (years whose number is a multiple of 100) whose number divided by 400 does not result in a natural number , not by a Leap day can be extended. The latter was the case in 1700, 1800 and 1900 and comes back in 2100, 2200, 2300, 2500 ... as opposed to 1600, 2000, 2400 ...

Different adoption of the Gregorian reform

In Reformed and Protestant areas, the calendar was adjusted later. These regions were not “papal believers” and therefore rejected this papal reform at the time. Another day difference was to be feared for the year 1700 due to the various leap year regulations. As a result, the Protestant German territories agreed at the Reichstag in Regensburg in 1699 and introduced an improved calendar that differed only slightly from the Catholic one. In the other European countries that still had the Julian calendar, the changeover took place at different times. The then rather sovereign Graubünden communities of Schiers and Grüsch were the last to convert in western Europe until 1812.

It is important to note these different points in time of the changeover when evaluating historical texts.

In Eastern Europe , the Russian Orthodox Church rejected the reform for similar reasons . In Russia and the other CIS states, public secular life has been based on the Gregorian calendar since the October Revolution (change from the 2nd (old calendar) to February 14, 1918). But the Orthodox Church holidays and related dates are still calculated according to the Julian calendar. It is similar in other Central and Eastern European countries with an Orthodox tradition.

Republican calendar after the French Revolution

The French revolutionary calendar represented a calendar that deliberately wanted to break with Christian tradition and introduce an internationally acceptable calendar based on rational principles. Its structure essentially corresponded to the ancient Egyptian calendar , the twelve months of which also comprised three decades each (one decade = ten days) and that at the end of common years five, but at the end of leap years six individual days (French sansculottids and Greek epagomens ) exhibited.

Soviet revolution calendar

It represented an anti-religious measure to create a new type of human being. An interrupted five-day work week with 12 months of 30 days each and 5 "non-annual" non-working days was supposed to eliminate the Christian Sunday as a day of rest, and thus a cultural break with the past produce. The length of the years and months has been retained.

See also

literature

  • Christine Gack-Scheiding: Johannes de Muris , Epistola super reformatione antiqui kalendarii: a contribution to the calendar reform in the 14th century (= Monumenta Germaniae historica, studies and texts , Volume 11), Hahn, Hanover 1995, ISBN 3-7752-5411-0 (Dissertation University of Tübingen 1993, 164 pages).
  • Edith Koller: Controversial Times: Calendar Reforms in the Old Empire 1582-1700 (= pluralization & authority , volume 41). De Gruyter, Berlin / Boston, MA 2014, ISBN 978-3-11-035891-9 (slightly edited and abridged version of the dissertation University of Munich 2009, 593 pages).
  • Tom Müller: "Ut reiecto paschali errore veritati insistamus": Nikolaus von Kues and his council paper De reparatione kalendarii (= book series of the Cusanus Society , Volume 17), Aschendorff, Münster 2010, ISBN 978-3-402-10456-9 (dissertation University of Trier 2009, 368 pages).
  • Heribert Smolinsky : Interpretations of the times in the conflict of denominations: controversial theology, apocalyptic and astrology in the 16th century ; presented on July 21, 2000 (= writings of the Philosophical-Historical Class of the Heidelberg Academy of Sciences ; Volume 20), Philosophical-Historical Class of the Heidelberg Academy of Sciences, Winter, Heidelberg 2000, ISBN 3-8253-1144-9 ).
  • Dirk Steinmetz: The Gregorian calendar reform of 1582: Correction of the Christian calendar in the early modern era , Steinmetz, Oftersheim 2011, ISBN 978-3-943051-00-1 (dissertation University of Heidelberg 2009/2010, 502 pages).

swell

  1. ↑ Roscoe Lamont: The Roman calendar and its reformation by Julius Caesar , Popular Astronomy 27 (1919) 583-595. Sacrobosco's theory is discussed on pages 585-587.
  2. ↑ See e.g. B. Egon Boshof, Kurt Düwell, Hans Kloft: Basics of the study of history. An introduction. Böhlau, Cologne et al. 1997 (5th edition), pp. 272f.
  3. ↑ Peter Aufgebauer : Between astronomy and politics. Gottfried Wilhelm Leibniz and the 'Improved Calendar' of the German Protestants, in: Niedersächsisches Jahrbuch für Landesgeschichte 81 (2009) 385-404.