Epoch (chronology)

Under epoch ( Greek Εποχή within the meaning of dt. Breakpoint ) is in the chronology of a new beginning of the era in each era understood.

Basics

The time of the epoch is usually a single day (epoch day ) that reflects a historical or fictional event, e.g. B. the beginning of a royal rule, the foundation of a city or the creation of the world. Only modern time systems also specify the time of the epoch.

The individual calendar systems deal with dates before their epoch in different ways: calendars that have calculated since the assumed creation of the world were initially not proleptic , that is, they knew no dates before the epoch. In the Gregorian calendar , the dates of the proleptic Julian calendar are used: Before January 1, 1 AD, this is December 31, 1 BC. Chr. In principle, based on epochs all dynastic calendar systems that start a new year count at the start of a new ruler or dynasty.

A calendar can be used with different epochs. For example, North Korea has a different era than most other countries that use the Gregorian calendar. Conversely, an epoch and the associated era can also be used by different calendars (such as Anno Hegirae ). There are also eras with several possible epochs. An example of this is ab origine mundi . It counts from the presumed creation of the world, which was dated to different points in time. An epoch can also apply to several eras. The North Korean Juche and Taiwanese Minguo calendars, for example, refer to different events, but have identical dates , since both events took place in 1912 AD.

Some epochs in chronological order

In addition to important epochs of historical chronology and the calendar , some epochs of astronomical chronology are also included, and in particular the Julian date JD, which provides the basis for converting the calendar systems, as well as contemporary dating epochs in data processing. In addition, the astronomical year count , which has some special features (e.g. year zero , sign) is shown.

Calendar eruptions

Epoch (dates BC)	Astronomical year count	JD ^*	Era / epoch	Calendar / time system	event
January 17, 998038	−998037		Years after the art	Julian calendar , Gregorian calendar	fictional first birthday of art set by the French artist Robert Filliou in 1963 AD (1,000,000 years before 1963)
January 1, 10000	0−9999		Holocene era / human era	Holocene Calendar , Davidian Martian Calendar	Approximate beginning of the Holocene
September 1, 5508	0−5507	.−290.130	Byzantine era Annus Mundi	Julian calendar	Creation of the world according to the genealogy of the Greek Bible Septuagint
January 1, 4713	0−4712	0.000.000	Julian day count	chronological Julian date	Beginning of the Julian period
January 1, 4000	0−3999	0.260.424	Anno Lucis	Julian / Gregorian calendar	Creation of the world according to the Masonic tradition
October 7, 3761	0−3760	0.347.998	Jewish era Anno Mundi	Jewish calendar	Creation of the world according to the Mosaic tradition
September 6, 3114	0−3113	0.584.283	Long count	Mayan Calendar	According to the Thompson correlation
January 1, 2333	0−2332	0.869.315	Dangun era	Korean lunisolar calendar, Julian / Gregorian calendar	Founding of Go-Joseon and Pyongyang on October 3rd, 2333 BC Chr .; used in South Korea from 1945 to 1961
March 21, 1738	0−1737	1,086,698	Zarathustra era	Zoroastrian calendar	Legendary birth of Zoroaster
January 1, 1166	0−1165	1,295,542	"Years of Our Lady of Discord "	Discordian calendar	Synchronization of the Discordian year with the founding year of Discordianism (1959 AD) through consistent application of the Law of Five (1959 - 5 ⁵ = −1166)
July 1, 0776	00−775	1,438,171	Olympic era	some greek calendars	1. Olympic Games
April 21, 0753	00−752	1,446,501	Varronic era	Roman calendar , Julian calendar	Founding of the city of Rome , from the urbe condita counting
April 21, 0752	00−751	1,446,866	Catonian / Capitoline count	Roman calendar , Julian calendar
February 26, 0747	00−746	1,448,638	Nabonassar era	Egyptian change year	The Babylonian king Nabû-naṣir takes office
February 11, 0660	00−659	1,480,400	Jimmu era	Gregorian calendar , Kōki	Japanese forging of an empire
January 1, 0544	00−543	1,522,728	Buddhist calendar	various calendars, e.g. B. Gregorian calendar, Chinese calendar , Thai lunar calendar , Suriyakati calendar or Tibetan calendar	presumed year of death of Siddhartha Gautama
April 3, 0311	00−310	1,607,923	Seleucid era	Macedonian calendar	Conquest of Babylon by Seleucus I.
January 1, 3800	000−37	1,707,544	Spanish era era	Julian calendar	unknown event, presumably the subjugation of Spain by the Romans; according to Isidore of Seville, however, a census by the emperor Augustus
January 1st000	0000± 0	1,721,058	Cassini chronology	Julian / Gregorian calendar	Year zero according to ISO 8601 and the astronomical year count
Epoch (dates AD)	Astronomical year count	JD ^*	Era / epoch	Calendar / time system	event
0January 1st000	0000+1	1,721,424	Christian calendar Anno Domini / Anno Salutis	Julian calendar, Gregorian calendar	Birth of christ
29 August 8000	0000+8	1,724,221	Christian calendar Anno Domini / Anno Salutis	Ethiopian calendar	Birth of christ
August 29, 2840	00+284	1,825,030	Diocletian era , era of martyrs	Julian calendar, Coptic calendar	Diocletian becomes emperor; under his rule the last persecutions of Christians take place
July 11, 5520	00+552	1,922,868	Old Armenian era	Armenian calendar	Foundation of the Armenian Apostolic Church
March 1, 6220	00+622	1,948,303	hijri shamsi (sun hijra)	Rumi calendar	Hijra
March 19, 6220		1,948,321	hijri shamsi (sun hijra)	Iranian calendar
July 16, 0622		1,948,440	hijri qamari (moon hijra)	Islamic calendar
June 16, 6320	00+632	1,952,063	Yazdgard era	Zoroastrian calendar	Accession to the throne of Yazdegerd III.
January 28, 1611	0+1611	2,309,493	Mars Daric year	Darian calendar	Development of Kepler's laws by Johannes Kepler and first observations of Mars with the help of a telescope by Galileo Galilei
January 1, 1789	0+1789	2,374,480	Années de la liberté	Positivist Calendar , French Revolution Calendar	Storming of the Bastille on July 14, 1789
September 22, 1792	0+1792	2,375,840	Années de la République Française	French revolutionary calendar	Proclamation of the First French Republic
March 21, 1844	0+1844	2,394,647	Badiʿ Era or Baha'i Era (B. E.)	Baha'i Calendar	Establishment of Babism in Shiraz (Iran) by the Bab (Seyyed ʿAli Muhammad Schirazi); the Baha'i later emerged from the Babitum
January 1, 1912	0+1912	2,419,403	Minguo era	Gregorian calendar	Xinhai Revolution
January 1, 1912	0+1912	2,419,403	Chuch'e era		Year of birth of Kim Il-sung
October 29, 1922	0+1922	2,423,357	Era fascista		Mussolini is sworn in as President of the Council of Ministers after the march on Rome
January 1, 1950	0+1950	2,433,283	Before Present	(cannot be converted directly into calendar years)	Timescale for dating past events with dates from radiocarbon dating
1st May 2019	0+2019	2,447,535	Reiwa time	Gregorian calendar	Accession of the Tennō Naruhito , current era of the dynastic system of Japan

^*While the astronomical Julian date counts the time since January 1st −4712 (4713 BC) 12 noon in days and fractions of days, only the integer day number (chronological Julian date) is required for the chronology. The 1st of January −4712 has the day number 0.

Time-accurate epochs

Epoch (dates BC)	Astronomical year count	JD ^*	Era / epoch	Calendar / time system	event
January 1, 4713 12:00:00 TT	−4712	0.000.000.0	Julian day count	Julian date	Beginning of the Julian period
Epoch (dates AD)	Astronomical year count	JD ^*	Era / epoch	Calendar / time system	event
January 1, 1601	+1601	2,305,824.0	Windows era	Microsoft Windows time	Start of time counting in Windows operating systems; was chosen because this date marks the start of the first 400 year cycle of the Gregorian calendar .
November 17, 1858 00:00:00 UT	+1 858	2,400,000.5	Era of MJD	Modified Julian date
January 1, 1970 00:00:00 UTC	+1970	2,440,587.5	UNIX epoch	Unix time	Beginning of Unix time counting (from UNIX version 6) - internal date widely used today in computer systems
January 6, 1980 00:00:00 UTC	+1980	2,444,243.5	GPS week 0	GPS time scale	Beginning of the GPS time system

^*The astronomical Julian date counts the time in days and fractions of days that has passed since 12 noon on January 1st −4712 (4713 BC). For time specifications that are precise to the second or even more precise, a time scale must also be specified . Without such an indication, the terrestrial time TT is meant in astronomy .

literature

Andreas Kamp: From Paleolithic to Postmodern - The genesis of our epoch system. Vol. I: From the beginning to the end of the 17th century. Amsterdam / Philadelphia 2010, ISBN 978-90-272-8736-6 .

Web links

Heinrich's homepage calendar converter , website with calendar converter (Julian & Gregorian calendar, Jewish calendar, Islamic calendar, French revolution calendar, Julian date)
Calendar calculator by Nikolaus A. Bär: conversion between dates of several ancient and modern calendars (Occident, Middle East, Iran) with output of JD for 12 o'clock; can also be run offline

Individual evidence

↑ Duden: The dictionary of origin. Etymology of the German language. Mannheim 2007, Lemma epoch.

↑ Why is the Win32 epoch January 1, 1601?

[1] Duden: The dictionary of origin. Etymology of the German language. Mannheim 2007, Lemma epoch.

[2] Why is the Win32 epoch January 1, 1601?