The Julian calendar is one of the oldest solar calendars and a forerunner of the Gregorian calendar in use today . He was born in 45 BC. Chr. By Julius Caesar - hence the name "Julian" calendar - introduced in the Roman Empire . He takes up the already 238 BC. Chr. Of Ptolemy III. Leap year regulation introduced in the Canopus Decree for the Egyptian administrative calendarwhich already back then provided for a leap day for every fourth calendar year. The Julian calendar is used retrospectively in science today for the years before Caesar's work.
As in the Egyptian administrative calendar, the year is divided into twelve months. Most of the month names were taken over from the Roman calendar (Ianuarius, Februararius, Martius, Aprilis ...), two were added (Iulius, Augustus). All month names live on in the Gregorian calendar to this day. Three common years with 365 days are followed by a leap year with February 29 as an additional day; The years are switched with a number divisible by four. The average year length is 365.25 days. It is about 11 minutes longer than the tropical year , which means that the beginning of spring shifts by one day towards the beginning of the year about every 128 years.
Since the 16th century, the Julian calendar was gradually replaced by the Gregorian calendar, which was improved from an astronomical point of view. During the conversion phase, contemporaries referred to the two calendars as "old" and "new style". In some parts of the world, the Julian calendar remained valid until well into the 20th century, and in the church sector to this day. Since March 1900 (and until February 28, 2100) there is a difference of 13 days between the two calendars , by which the Julian calendar lags behind the Gregorian calendar. For example, if it is January 7th according to the Gregorian calendar, then according to the Julian calendar it is not until December 25th. Therefore, Christmas in many churches falls on January 7th, Gregorian style. These include many Orthodox churches (e.g. the Patriarchate of Jerusalem , the Patriarchate of Moscow , the Georgian Patriarchate , the Serbian Patriarchate and the Orthodox Church of Ukraine and the Archdiocese of Ohrid in North Macedonia ) as well as numerous ancient oriental churches ( Syrians , Copts , Ethiopians , Eritreans and the Armenian Apostolic Patriarchate of Jerusalem ).
Caesar's calendar reform
Appian , Cassius Dio and Macrobius report in their writings that Julius Caesar was born in 47 BC. Got to know the switching cycle of the later Julian calendar in Hellenized Egypt in Alexandria . The additional information provided by Macrobius therefore allows Julius Caesar to travel to Egypt to discuss the new form of the Julian calendar with experts on the Egyptian calendar , probably with the Egyptian astronomer Sosigenes , among others , after Julius Caesar went through the Egyptian calendar Acoreus had gotten to know better.
This new calendar - later called "Julian" in his honor - came into being in 45 BC. In force. It consisted of eleven months of 30 or 31 days each and one month of 28 days. The old names from the Roman calendar were initially retained. The confused year 708 a. u. c. was extended to 445 days and began on October 14, 47 BC. Chr. In the old Roman calendar was in leap years shortened the February first 23 days and the leap month mercedonius added that in addition included the shortened remaining days of February. This leap month no longer applies due to the reform.
|Change of the day division into the months (modern month names) due to the Julian calendar reform|
|old Roman calendar
until 46 BC Chr.
from 45 BC Chr.
The switching rule was interpreted literally by the pontifices after Caesar's death , but this led to incorrect switching. Caesar had ordered the switching every fourth year, but the priests understood this to be a switching every three years according to the inclusive count . This is believed to be the oldest known example of a fence post failure . The too many leap years were corrected by the Emperor Augustus by revising the circuit in the years 5 BC. BC, 1 BC And 4 AD and did not resume until 8 AD. As a result of this initial year of the regular inclusion of a leap year, since then the years with a year divisible by 4 have been leap years.
Contrary to medieval interpretations, Augustus did not change the distribution of the days over the months.
Beginning of the year
The Julian calendar itself was recognized throughout the Roman Empire, but the beginning of the year was handled differently from region to region. The beginning of the year was after the Roman calendar v until the year 153rd Chr. On March 1st . In ancient Rome this day was originally the beginning of the calendar year on which the sacred fire was lit in the temple of Vesta . In 153 BC . AD who had Roman consuls their rule on January 1 brought forward, it was also the beginning of its term of office, the new beginning of the year.
In Egypt the turn of the year was on August 29th, in Constantinople and later also in Russia on September 1st, in the western Mediterranean as well as common in England , Germany and Switzerland on December 25th, later in Great Britain on March 25th and in others Countries on other days. It was not until the early modern period that January 1st became more or less general in the west, and not until the early 18th century in the east.
The counting of the year was also different in different parts of the Roman Empire; in the west, the number was usually not counted at all, but the years were named after the two consuls who held office for a year . In addition, the count " from the foundation of the city (Rome) " and later the Diocletian era was used. In the east, the Seleucid era was common, the 312 BC. When year one counted. Later, the Christian time calculation , which is still common today, prevailed in the West ; in the East, the time calculation “from the creation of the world ” was still common; this was by the Byzantines to the year 5509 BC. BC.
In 44 BC Was renamed the Quintilis (originally "fifth month", since 153 BC the seventh) by the Lex Antonia de mense Quintili Julius Caesar in honor of Julius . Later the sextilis (originally “sixth month”, since 153 BC the eighth) received its new name in honor of Emperor Augustus.
The calendar at the time of the Roman Empire had the following twelve or thirteen months:
- Mensis intercalaris (omitted due to the introduction of the Julian calendar)
- Iulius (originally Quintilis)
- Augustus (originally Sextilis)
Other months were also temporarily named after Roman rulers, but apparently none of these changes survived their deaths. Caligula called September (seventh month) Germanicus ; Nero named Aprilis (second month) Neroneus , Maius (third month) Claudius, and Junius (June) Germanicus; Domitian called September Germanicus and October (eighth month) Domitianus . September was also renamed Antoninus and Tacticus , November (ninth month) also got the names Faustina and Romanus . Commodus was unique in that he named after his adopted names every twelve months (January to December): Amazonius, Invictus, Felix, Pius, Lucius, Aelius, Aurelius, Commodus, Augustus, Herculeus, Romanus, and Exsuperatorius.
Charlemagne later named every month with mostly agricultural terms in the vernacular of the time, Old High German . The German names were further developed differently from region to region and continued to be used until the 15th century and, with some changes, until the late 19th century.
|Old High German||Middle High German||early new high German||German|
|Charlemagne (around 800)||Herrad v. Landsberg (around 1200)||Regiomontanus (1473)||(around 2000)|
Transition to the Gregorian calendar
The Julian year is 11 minutes and 14 seconds too long compared to the solar year . This led to an increasing deviation from the course of the sun, which was already more than seven days in the 14th century. Another reason for the Gregorian reform was the spring full moon , which was incorrectly determined with the old Easter formula and on which the Easter date depends.
Pope Gregory XIII introduced the Gregorian calendar with an improved switching rule in 1582 . This states that full centuries (like 1700, 1800, 1900, etc.) are only leap years if they are divisible by 400. So, for example, 2000 was a leap year, but 1900 was not.
For the transition, Gregory XIII determined. Furthermore, Thursday, October 4th, 1582 (Julian) had to be followed directly by Friday, October 15th, 1582 (Gregorian), with which 10 days were skipped (while maintaining the weekday sequence). Since the new calendar was introduced by the Pope , it was initially mainly used by the Roman Catholic states. Most Protestant states kept the Julian calendar until the 18th century, which led to a cumbersome juxtaposition of "old style" with "new style", especially in mixed denominational areas of Germany. In the Protestant imperial estates of the Holy Roman Empire, the conversion took place on February 18, 1700, which was immediately followed by March 1, “new style”. Most of the reformed places of the Swiss Confederation changed after December 31, 1700 "old style" to January 12, 1701 "new style"; the last Graubünden municipalities, Schiers and Grüsch , did not follow until 1812.
Russia long stuck to the Julian calendar due to the influence of the Orthodox Church on public life. The changeover took place after the October Revolution on February 1st July. / February 14, 1918 greg. The lag between the Julian and the Gregorian calendar had increased by three more days to 13 days since 1582. The name "October Revolution" was retained, although it now took place in November according to the Gregorian calendar.
Today's use of the Julian calendar
Some of the Orthodox churches (e.g. the Russian, Syrian, Serbian, Georgian, Macedonian, Ukrainian) continue to celebrate all their festivals according to the Julian calendar. Your Christmas party (December 25th) currently falls on January 7th (Gregorian).
To determine the date of Easter and the other movable festivals, the Julian calendar and the old Easter formula coupled with it are used in all Orthodox churches (except the Finnish one). They therefore only occasionally coincide with the corresponding festivals of the Western churches, usually one to five weeks later.
The following autocephalous and autonomous Orthodox churches use the Julian calendar: Patriarchate of Jerusalem , Patriarchate of Moscow, Patriarchate of Serbia, Patriarchate of Georgia, Church of Sinai, Church of Japan, Church of China, Church of Ukraine, Archdiocese of Ohrid, Church of Albania , Holy Mount Athos . It is also used by splits from the Greek Orthodox Church as well as the Syrian, Coptic, Ethiopian Churches and the Armenian Apostolic Patriarchate of Jerusalem.
Regardless of the time of the legal introduction of the Gregorian calendar in the various European countries, all historical dates since October 15, 1582 have always been converted into Gregorian.
In Central Europe there are still customs that are based on the Julian calendar, such as the old New Year's Eve in the Appenzell hinterland . New Year's Eve is celebrated there on January 13th (Gregorian).
The Julian calendar year lasts 365.25 days or 365 days and 6 hours. In the Julian calendar, the leap year cycle is four years. A period of 100 years in the Julian calendar (e.g. from April 12, 1 4 24 noon to April 12, 1 5 24 noon) therefore always contains an integer number of leap year cycles and therefore always the same number of days, namely 36,525. In contrast, a century in the Gregorian calendar can be either 36,524 days (e.g., April 12, 1724 noon to April 12, 1824 noon) or 36,525 days (e.g., April 12, 1924 noon to April 12 2024 noon) included. Because of this conceptual clarity, the integers and the practical proximity to the duration of 100 tropical years (36,524.219 ... days), the so-called Julian century is used to 36,525 days as a convenient time unit in astronomical formulas.
For example, it can be seen from relevant tables that the position of the perihelion of the earth's orbit shifts along the orbit at a speed of 0.323 degrees per Julian century. In this context, a day is generally to be understood as the ephemeris day consisting of 86,400 seconds (of the International System of Units ) , so that the Julian century is only an intuitively easy to understand name for a period of 3,155,760,000 seconds.
- List of calendar systems
- Conversion between the Julian and Gregorian calendar
- Conversion between the Julian date and the Gregorian calendar
- Conversion between the Julian date and the Julian calendar
- Jörg Rüpke : Time and Feast: A Cultural History of the Calendar . Beck, Munich 2006, ISBN 3-406-54218-2 .
- Jörg Rüpke: Calendar and Public: The History of Representation and Religious Qualification of Time in Rome . de Gruyter, Berlin 1995, ISBN 3-11-014514-6 .
- Friedrich Karl Ginzel : Handbook of mathematical and technical chronology. Vol. 2: Calculation of the times of the Jews, the primitive peoples, the Romans and Greeks as well as addenda to the 1st volume Austrian Literature Online, Innsbruck 2007 (reprint of the original Leipzig edition 1906) ISBN 3-226-00428-X , pp. 274-275 .
- Jörg Rüpke: Time and Feast: A cultural history of the calendar . P. 33.
- Macrobius, Saturnalia 1, 14, 7.
- Sacha Stern: Calendars in Antiquity . Oxford University Press, 2012. Note 155 at p. 212.
- Karl Weinhold : The German names of the months , Halle 1869, pp. 5-8. Digitized
- Hellmut Gutzwiller : Calendar. In: Historical Lexicon of Switzerland . January 15, 2018 , accessed June 4, 2019 .