Historical chronology

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The historical chronology is that part of the chronology (chronology) which deals with the historical development of the calendar system and the earlier handling of time.

In addition to the historical chronology, one differentiates

A further differentiation is made according to the different dating methods:

Historical chronology tasks

Actually, every historian is also active chronologically when it comes to classifying past events on a time scale . He has to do with various calendars, month and year lengths, and also with year counts in an era that depends on the country (see below).

The creation of a chronological order

  • can be relative (mere chronological order), e.g. the succession of rulers of a country,
  • or on a fixed time scale, i.e. a calendar .
  • An absolute dating, however, is only given when the time scale is clearly related to the present . The astronomical chronology is ideal for this, if you find reports about eclipses or planetary constellations.

Cultural-ideological influences

The town hall in Merano in South Tyrol was built in ANNO VII after the March on Rome (1922).

In doing this chronological activity, the historian also has to take into account the cultural aspects of the time he is investigating, but philosophical and ideological aspects also influence the calculation of time. This can be seen at the beginning of the respective year count: years since the creation of the world ( Byzantine era), years before and after the birth of Christ , use of a festival calendar ( Christmas , Easter , Pentecost , ...) or its secularized forms ( Valentine's and Mother's Day , Father's Day , Day of German Unity , etc.).

The introduction of these eras, however, often took place at a long time interval from the historical epoch day , whether it is the calculation from urbe condita (Rome's legendary foundation in 753 BC), the year of incarnation , the Byzantine world era, the hijra (Muhammad's flight 622) , the French revolutionary calendar (valid from November 1793, but counting started in 1792) or the fascist era in Italy (from March on Rome 1922). Long discussions about the turn of the century and millennium are therefore of little use.

Since the Middle Ages , in addition to dates in the Roman calendar, days of the Christian calendar of saints have been used, but today only Martin, Valentin, Johannes ( midsummer fire ), Stefan and New Year's Eve are generally known, as well as some Marian festivals and the movable festivals (Easter, Pentecost, Corpus Christi , Advent Sundays ).

Reference points and "eras"

Every precise chronology requires a reference point in the flow of time from which the hours, days, weeks, months and years are counted up or down.

Hour counting, day and week

When counting the hours, the one from sunrise is probably the oldest (see also Babylonian hours ). Today one counts equal hours from midnight , while the Julian date (JD) of astronomers begins at noon . In ancient times, the hours were often assigned a planetary deity , after which our days of the week are named. In the past, the night was often divided into night watches, with the often-cited last night watch actually counting backwards from sunrise.

The day (more precisely: sunny day ) is the only time measurement that is uniform worldwide. The seven-day weekly cycle originates from the Babylonians and has been counting continuously since then. In some cultures there were also cycles between five and ten days, and attempts to introduce a ten-day week were also made during the French Revolution. The seven-day week, however, is predominant because it best suits the change in the phases of the moon.

month and year

The next longer period of time, the month , is also adapted to the lunar orbit of (apparently) 29½ days . Presumably there are also connections with the female cycle . In earlier cultures there were month lengths of very different (also changing) lengths and also different forms of the leap month .

Because the synodic lunar orbit (on average 29.5306 days) and the year are not compatible: 12 mean lunations only make up 354.37 days, 13 however 383.90 days (therefore the old Chinese year, for example, can have 353 to 385 days). The importance of a culture to the phases of the moon ultimately decided on the introduction of a pure lunar or solar calendar or a hybrid of both ( lunisolar calendar ). Since further details are possible, there have been a wide variety of calendars around the world and also repeated calendar reforms .

The year also has a slightly different length depending on the reference point, but the differences are insignificant for most purposes:

  • Tropical year 365.2421 90517 days
  • Sidereal year 365.2563 6042 days (both for J2000.0 )
  • Julian year 365.25 days (and some other definitions)
  • Calendar year 365 or 366 days
  • Church year mostly 364 days (depending on the beginning of Advent ).

While the month of a lunar calendar usually begins at the new moon or at the so-called new light (1–2 days later), there are several options for the beginning of the year . Most early cultures put him near the winter solstice or spring day and night are equally long .

On the importance of the era

In order to cover longer periods of time from years to decades, special "eras" have been introduced and based on an excellent event as a starting point from which the years are counted. As far as historical research has shown, forms of chronology of the era were introduced late. Interestingly enough, however, ancient peoples of the highest technical level, such as the Egyptians , Babylonians or Assyrians , used a continuous era as a reference scale for a long time.

The era of the Greeks is therefore probably the earliest example and probably only came into use in the 4th century BC. The Greeks counted the years after the Olympics , that is, in periods of four years. The year 776 BC BC was considered the year of the first Olympiad. In addition, special years were often marked by relating them to the term of office of certain officials.

The latter form was also used in the Roman Empire - alongside the official ab -urbe condita years. A particularly detailed example of the dating of a person can be found in the Gospel according to Luke (Chapter 3) about the public appearance of John the Baptist : It was in the fifteenth year of the reign of Emperor Tiberius ; Pontius Pilate was governor of Judea, Herod the tetrarch of Galilee, his brother Philip the tetrarch of Iturea and Trachonitis, Lysanias the tetrarch of Abilene; Annas and Caiaphas were high priests . The word of God came to John, son of Zacharias, in the desert ...

Chronological eras

Distinctive turning points in historical chronology are the times when a new calendar was introduced. The most important for Europe are:

  • Jewish calendar , one of the oldest in the world. It is currently (2015) in the year 5775/5776.
  • Babylonian era : from a mythical creation date ~ 5000 BC Chr.
  • Era of Claudius Ptolemy , which, according to his astronomical textbook Almagest, begins with the accession of the Babylonian king Nabû-naṣir (in today's calendar 747 BC)
  • Roman Era : Since around 400 BC BC one often counted away from the dedication of the Temple of Jupiter on the Capitol , the 507 BC. Took place. Later the years “ ab urbe condita ” (a. U. C.) Were counted, “from the founding of the city” (meaning Rome ). In the empire there was also "per Anno Diokletiani " (AD), which should not be confused with the Christian " Anno Domini ":
  • Christian era (system of the chronologist Dionysius Exiguus ): our current year counting. It was introduced after lengthy research in the year 525 and begins with the year 754 from urbe condita , the supposed year of the birth of Christ .
  • Islamic era : it begins with the Hijra , the flight of Muhammad from Mecca in the year 622. Due to the purely lunar calendar, the Muslim New Year (1st Muharram) shifts annually by 10 to 12 days: New Year 1426 was February 10, 2005, 1427 on January 31, 2006. It is true that 1384 years, not 1427, have passed since the Hejra.
  • Byzantine Empire : the era counted from the creation of the world , which according to the genealogy of the Greek Bible ( Septuagint ) to the year 5501 or 5508 BC. Was dated. This count lasted in Russia until the end of 1699, when Peter the Great ordered that from the New Year, instead of 7208 NEdW ("after the creation of the world"), 1700 AD should be written.
  • Julian calendar (mean annual length 365.25 days): it was introduced by Gaius Iulius Caesar , has a leap day exactly every four years and was in some places still valid into the 20th century, in the Orthodox churches until today. Scientists use it retrospectively for the years before the new era .
  • Gregorian calendar (mean year length 365.2425 days): it replaced (different from country to country) from 1582 the Julian calendar, from which it differs through the rule of the century . In order to correct the accumulated 10-day error, October 4, 1582 had to be directly followed by October 15, 1582.
  • Julian date (JD): a continuous day count from the year -4712 (= 4713 BC). They are used in astronomy and geosciences when one has to avoid the problem of unequal centuries (36,524 or 36,525 days). In JD, for example, noon on January 1, 2006 has the day number JD = 2,453,737 (2,453,737 days since the beginning of the year of 4713 BC).
  • Modified Julian Date (MJD): a modification of the JD introduced around 1960 for satellite geodesy , which is reduced by 2,400,000.5 days. So you get smaller numbers and a day start at midnight Greenwich ( 0:00 UT ) instead of 12:00 UT. MJD is now used less often.

Comparative chronology

An important task of historical chronology is a reliable conversion between these time scales. It requires not only historical but also astronomical knowledge and a thorough study of the sources, especially those times when a new calendar was introduced. Today, knowledge of electronic data processing is also essential.

Although the conversions are supported by numerous computer programs, errors in the algorithms keep coming to light. Checks with some tried and tested tables are recommended here , for example that by Paul Oswald Ahnert .

Dating from sources that only have vague information about the time or that refer exclusively to government years and the like are also a major challenge . The succession of rulers can be incomplete due to mistakes or political intent, individual years can be counted twice or skipped (see inclusive counting and epoch leap ). In this way, the chronologist Dionysius Exiguus presumably "lost his mind" in the year 525 when he worked out our Christian calendar.

In addition to these ancient problems, historical chronology researches, among other things, the changing designs of the Roman calendar and the medieval festival calendar or the French revolutionary calendar . Researching pre-Columbian eras - such as the Maya era, which also included the planet Venus - and the calendar clarification of old travel reports is a challenging topic.

Also of interest are regional dating styles such as ruler dating, regional festival calendars, the stilus pisanus / stilus florentinus / Bolognese style and the above-mentioned eras, such as the Byzantine and Jewish World Era , the Spanish Era or other regional dates. As an aid to such dating problems There are some specialist books with corresponding tables, for example a pocket book on the calculation of time by the German chronologist Hermann Grotefend , which deals with a number of unfamiliar dating styles.

Specific chronologies

literature

Web links

Wikisource: Chronology  - Sources and Full Texts