Calendar era

2024 in variouscalendars

Gregorian calendar	2024 MMXXIV
Ab urbe condita	2777
Armenian calendar	1473 ԹՎ ՌՆՀԳ
Assyrian calendar	6774
Baháʼí calendar	180–181
Balinese saka calendar	1945–1946
Bengali calendar	1431
Berber calendar	2974
British Regnal year	2Cha. 3– 3Cha. 3
Buddhist calendar	2568
Burmese calendar	1386
Byzantine calendar	7532–7533
Chinese calendar	Quý mãoNiên (WaterRabbit) 4721 or 4514 — to — Giáp thần niên (WoodDragon) 4722 or 4515
Coptic calendar	1740–1741
Discordian calendar	3190
Ethiopian calendar	2016–2017
Hebrew calendar	5784–5785
Hindu calendars
-Vikram Samvat	2080–2081
-Shaka Samvat	1945–1946
-Kali Yuga	5124–5125
Holocene calendar	12024
Igbo calendar	1024–1025
Iranian calendar	1402–1403
Islamic calendar	1445–1446
Japanese calendar	Reiwa6 ( lệnh hòa ６ niên )
Javanese calendar	1957–1958
Juche calendar	113
Julian calendar	Gregorian minus 13 days
Korean calendar	4357
Minguo calendar	ROC113 Dân quốc 113 niên
Nanakshahi calendar	556
Thai solar calendar	2567
Tibetan calendar	Âm thủy thỏ niên (female Water-Rabbit) 2150 or 1769 or 997 — to — Dương mộc long niên (male Wood-Dragon) 2151 or 1770 or 998
Unix time	1704067200 – 1735689599

Acalendar erais the period of time elapsed since oneepochof acalendarand, if it exists, before the next one.For example, it is the year2024as per the Gregorian calendar, which numbers its years in the WesternChristian era(theCoptic OrthodoxandEthiopian Orthodoxchurches have their own Christian eras).

In antiquity,regnal yearswere counted from the accession of a monarch. This makes thechronology of the ancient Near Eastvery difficult to reconstruct, based on disparate and scattered king lists, such as theSumerian King Listand the BabylonianCanon of Kings.In East Asia, reckoning byera nameschosen by ruling monarchs ceased in the 20th century except forJapan,where they are still used.

Ancient dating systems

Assyrian eponyms

Main article:Eponym dating system

For over a thousand years, ancientAssyriaused a system ofeponymsto identify each year. Each year at theAkitufestival (celebrating the Mesopotamian new year), one of a small group of high officials (including the king in later periods) would be chosen by lot to serve as thelimmufor the year, which meant that he would preside over the Akitu festival and the year would bear his name. The earliest attestedlimmueponyms are from the Assyrian trading colony atKarum Kaneshin Anatolia, dating to the very beginning of the 2nd millennium BC,and they continued in use until the end of theNeo-Assyrian Period,c. 612 BC.

Assyrian scribes compiledlimmulists, including an unbroken sequence of almost 250 eponyms from the early 1st millennium BC. This is an invaluable chronological aid, because a solar eclipse was recorded as having taken place in thelimmuof Bur-Sagale, governor ofGuzana.Astronomers have identified this eclipse asone that took place on 15 June 763 BC,which has allowed absolute dates of 892 to 648 BC to be assigned to that sequence of eponyms.This list of absolute dates has allowed many of the events of the Neo-Assyrian Period to be dated to a specific year, avoiding thechronological debatesthat characterize earlier periods of Mesopotamian history.

Olympiad dating

Among the ancient Greek historians and scholars, a common method of indicating the passage of years was based on theOlympic Games,first held in776 BC.The Olympic Games provided the various independent city-states with a mutually recognizable system of dates. Olympiad dating was not used in everyday life. This system was in use from the 3rd century BC. The modern Olympic Games (or Summer Olympic Games beginning 1896) do not continue the four year periods from ancient Greece: the 669th Olympiad would have begun in the summer of 1897, but the modern Olympics were first held in 1896.

Indiction cycles

Theindictioncycle was an agricultural tax cycle implemented in Roman Egypt. 15 indictions made up the cycle, an indiction being a year in duration. Documents and events began to be dated by the year of the cycle (e.g., "fifth indiction", "tenth indiction" ) in the 4th century, and this system was used long after the tax ceased to be collected. It was used inGaul,inEgyptuntil theIslamic conquest,and in theEastern Roman Empireuntil its conquest in 1453.

A useful chart providing all the equivalents can be found in Chaîne's book on chronology,and can easily be consulted online at the Internet Archive, frompage 134topage 172.

A rule for computing the indiction from an AD year number was stated byDionysius Exiguus:add 3 and divide by 15; the remainder is the indiction, with 0 understood to be the fifteenth indiction.Thus the indiction of 2001 was 9.The beginning of the year for the indiction varied.

Seleucid era

Main article:Seleucid era

The Seleucid era was used in much of the Middle East from the 4th century BC to the 6th century AD, and continued until the 10th century AD among Oriental Christians. The era is computed from the epoch 312 BC: in August of that yearSeleucus I NicatorcapturedBabylonand began his reign over the Asian portions ofAlexander the Great's empire. Thus depending on whether the calendar year is taken as starting on 1Tishrior on 1Nisan(respectively the start of the Jewish civil and ecclesiastical years) the Seleucid era begins either in 311 BC (the Jewish reckoning) or in 312 BC (the Greek reckoning: October–September).

Ancient Rome

Consular dating

An early and common practice was Roman 'consular' dating. This involved naming bothconsules ordinariiwho had taken up this office on 1 January (since 153 BC) of the relevant civil year.Sometimes one or both consuls might not be appointed until November or December of the previous year, and news of the appointment may not have reached parts of the Roman empire for several months into the current year; thus we find the occasional inscription where the year is defined as "after the consulate" of a pair of consuls.

The use of consular dating ended in AD 541 when the emperorJustinian Idiscontinued appointing consuls. The last consul nominated wasAnicius Faustus Albinus Basilius.Soon afterwards, imperial regnal dating was adopted in its place.

Dating from the founding of Rome

Another method of dating wasab urbe condita(Latin for "from the founding of the city" of Rome) oranno urbis conditae(Latin for "in the year of the founding of the city" ), both abbreviated AUC.

Several epochs for this date were in use byRoman historians,all based on the incomplete survivinglist of Roman consulsand themythsof thecity's foundingbyRomulus and Remus.Thechronologyestablished byMarcus Terentius Varroin the 1st century BC intercalated several years ofdictatorships,a period of anarchy, and a standardized length of reign for all of Rome'sformer kingsto arrive at a year running from 754–753BC,taken as equivalent to the 3rd year of the 6th Olympiad. Because thePariliahad become associated with the founding of the city by his time, he took the specific date to have been 21 April 753BC. This became the official chronology of the empire by at least the time ofClaudius,who heldSecular Gamesin AD 47 to celebrate the city's 800th anniversary. The 900th and 1000th anniversaries were then celebrated in 148 underAntoninus Piusand in 248 underPhilip I.

The AUC era was seldom used in thetraditional Romanorearly Julian calendars.Naming each year by itstwo consulsor by the emperor's regnal years predominated, withHadrian'saureiandsestertiimarking theRomaeain AUC 874 (ann dccclxxiiii nat vrb) a notable exception.AUC dating became more common in late antiquity, appearing inCensorinus,Orosius,and others. During the early Middle Ages, some church officials likeBoniface IVemployed AUC and AD dating together.

Historical Roman dating employed several different dates for the beginning of the year. Modern application of the AUC era generally ignores this, the known mistakesin Varro's own calculations, and the 752BC epoch used by theFastiand later Secular Games, such that AD 2024 is generally considered equivalent to AUC 2777 (2024 + 753).

Regnal years of Roman emperors

Another system that is less commonly found than might be thought was the use of theregnal yearof theRoman emperor.At first,Augustusindicated the year of his reign by counting how many times he had held the office of consul, and how many times theRoman Senatehad granted him thepower of a tribune(Latin:tribunicia potestas,abbr. TRP), carefully observing the fiction that his powers came from these offices granted to him, rather than from his own person or the manylegionsunder his control. His successors followed his practice until the memory of theRoman Republicfaded (about AD 200), when they began to use their regnal year openly.

Dating from the Roman conquest

Some regions of theRoman Empiredated their calendars from the date of Roman conquest, or the establishment of Roman rule.

TheSpanish eracounted the years from 38 BC, probably the date of a new tax imposed by the Roman Republic on the subdued population of Iberia. The date marked the establishment of Roman rule in Spain and was used in official documents in Portugal,Aragon,Valencia,and inCastile,into the 14th century. This system of calibrating years fell to disuse in 1381 and was replaced by today'sAnno Domini.

Throughout the Roman and Byzantine periods, theDecapolisand other Hellenized cities of Syria and Palestine used thePompeian era,counting dates from the Roman generalPompey's conquest of the region in 63 BC.

Maya

A different form ofcalendarwas used to track longer periods of time, and for the inscription of calendar dates (i.e., identifying when one event occurred in relation to others). This form, known as theLong Count,is based upon the number of elapsed days since a mythological starting-point. According to the calibration between the Long Count and Western calendars accepted by the great majority of Maya researchers (known as the GMT correlation), this starting-point is equivalent to 11 August, 3114 BC in the proleptic Gregorian calendar or 6 September in the Julian calendar (−3113 astronomical).

Other dating systems

A great many local systems oreraswere also important, for example the year from the foundation of one particular city, the regnal year of the neighboringPersian emperor,and eventually even the year of the reigningCaliph.

Late Antiquity and Middle Ages

Most of the traditional calendar eras in use today were introduced at the time of transition fromLate Antiquityto theEarly Middle Ages,roughly between the 6th and 10th centuries.

Christian era

• TheEtos Kosmouof theByzantine Calendarcommences with thecreation of the worldportrayed inGenesis,the date of which- arrived at by the monk Giorgios- being 1 September, 5509 BC. Its first known use occurred in the 7th century AD, although its precursors were developed about AD 400.
• TheEra of Martyrsor Era of Diocletian is reckoned from the beginning of the reign of Roman EmperorDiocletian;the first year of this era was 284/5. It was not the custom to use regnal years in Rome, but it was the custom in Roman Egypt, which the emperor ruled through a prefect (the king of Egypt). The year number changed on the first day of the Egyptian monthThoth(29 August three years out of four, 30 August the year before a Roman leap year.) Diocletian abolished the special status of Egypt, which thereafter followed the normal Roman calendar: consular years beginning on 1 January. This era was used in the Easter tables prepared in Alexandria long after the abdication of Diocletian, even though Diocletian was a notorious persecutor of Christians. The Era of Diocletian was retained by theCoptic Churchand used for general purposes, but by 643 the name had been changed to Era of the Martyrs.
• TheIncarnation Erais used byEthiopia.Its epoch is 29 August, AD 8 in the Julian calendar.
• TheArmenian calendarhas its era fixed at AD 552.

Dionysian "Common Era"

Main articles:Anno DominiandCommon Era

The era based on theIncarnationofChristwas introduced byDionysius Exiguusin 525 and is in continued use with various reforms and derivations. The distinction between the Incarnation occurring with theconceptionor theNativity of Jesuswas not drawn until the late ninth century.The first day of the numbered year varied from place to place and depended on the calendar in use: when, in 1600, Scotland adopted 1 January as the first day of the year, this was already the case in much of continental Europe. England adopted this practice in 1752.

• A.D. (or AD) – for theLatinAnno Domini,meaning "in the year of (our) Lord". This is the dominant or Western Christian Era; AD is used in the Gregorian calendar.Anno Salutis,meaning "in the year of salvation" is identical. Originally intended to number years from the Incarnation ofJesus,according to modern thinking the calculation was a few years off. Years preceding AD 1 are numbered using the BC era, avoiding zero or negative numbers. AD was also used in the ChristianizedJulian calendar,but the first day of the year was either 1 March,Easter,25 March (Feast of the Annunciation), 1 September, or 25 December (Feast of the Nativity), not 1 January. To distinguish between the Julian and Gregorian calendars,O.S.andN.S.were often added to the date, especially during the 17th and 18th centuries, when both calendars were in common use.Old Style(O.S.) was used for the Julian calendar and for years not beginning on 1 January.New Style(N.S.) was used for the Gregorian calendar and for Julian calendar years beginning on 1 January. Many countries switched to using 1 January as the start of the numbered year at the same time as they switched from the Julian calendar to the Gregorian calendar, but others switched earlier or later.
• B.C. (or BC) – meaning "Before Christ". Used for years before AD 1, counting backwards so the yearnBC isnyears before AD 1. Thus there is noyear 0.
• C.E. (or CE) and B.C.E. (or BCE) – meaning "Common Era"and" Before the Common Era ", numerically equivalent to AD and BC, respectively (in writing," AD "precedesthe year number, but "CE"followsthe year: AD 1 = 1 CE.)The Latin equivalentvulgaris aerawas used as early as 1615 byJohannes Kepler.The English abbreviations C.E. and B.C.E. were introduced in the 19th century by Jewish intellectuals, wishing to avoid the abbreviation fordominus"lord" in implicit reference to Christ.By the later 20th century, the abbreviations had come into wider usage by authors who wished to emphasizesecularism.

Dionysian-derived

• Astronomical year numberingsituates its year 0 with 1 BC, and counts negative years from 2 BC backward (−1 backward), so 100 BC is −99.
• Thehuman era,also named Holocene era, proposed byCesare Emilianiadds 10,000 to AD years, so that AD 1 would be the year 10,001.
• Anno LucisofFreemasonryadds 4000 years to the AD year.

Islamic

• A.H.(or AH) for the LatinizedAnno Hegirae,meaning "in the year of theHijra",Muhammad's emigration from Mecca to Medina in September 622, which occurred in its first year, is used in theIslamic calendar.Since the Islamic calendar is a purelylunar calendarof about 354 or 355 days, its year count increases faster than that ofsolarandlunisolar calendars.
• S.H.(or SH)is used by theIranian calendarto denote the number ofsolaryears since the Hijra. The year beginning at the vernal equinox equals the number of the Gregorian year beginning at the preceding 1 January minus 621.

Hindu

• Hindu calendar,counting from the start of theKali Yuga,with its epoch on 18 February, 3102 BC Julian (23 January, 3102 BC Gregorian), based on Aryabhata (6th century).
• Vikrama Samvat,56-57 BC, introduced about the 12th century.
• S.E.or (SE) – for theSaka Era,used in someHindu calendarsand in theIndian national calendar,with an epoch near the vernal equinox of year 78 (its year 0); its usage spread to Southeast Asia before year 1000. This era is also used (together with the Gregorian calendar) in the Indian national calendar, the official civil calendar used in communiques issued by the Government of India.
• Lakshmana Era,established by theBengalirulerLakshmana Senawith an epoch of 1118–1119. It was used for at least 400 years in Bihar and Bengal.

Southeast Asia

The Hindu Saka Era influences the calendars of southeast Asianindianized kingdoms.

• B.E.– for theBuddhist Era,introduced byVajiravudhin 1912, which has anepoch(origin) of 544 BC. This year is called year 1 inSri LankaandBurma,but year 0 inThailand,LaosandCambodia.Thus the year 2500 B.E. occurred in 1956 in the former countries, but in 1957 in the latter. In Thailand in 1888 KingChulalongkorndecreed a National Thai Era, dating from the founding ofBangkokon 6 April 1782. In 1912 New Year's Day was shifted to 1 April. In 1941 Prime MinisterPhibunsongkhramdecided to count the years since 543 BC. This is theThai solar calendarusing the Thai Buddhist Era aligned to the western solar calendar.
• BEfor Burmese Era – fromBurmese calendaroriginally with an epochal year 0 date of 22 March 638; from which derivedCSforChula Sakaratera; variously known asLELesser Era;MEMinor Era – the Major or Great Era being theSaka Eraof theIndian national calendar

B.E. of the Bahá'í calendar is below.

Bahá'í

• B.E.– TheBahá'í calendardates from the year of the declaration of theBáb.Years are counted in the Bahá'í Era (BE), which starts its year 1 from 21 March 1844.

Jewish

• A.M.(or AM) – for the LatinAnno Mundi,meaning "in the year of the world", has its epoch in the year 3761 BC. This was first used to number the years of the modernHebrew calendarin 1178 byMaimonides.Precursors with epochs one or two years later were used since the 3rd century, all based on theSeder Olam Rabbaof the 2nd century. The year beginning in the northern autumn of 2000 was 5761 AM.

Zoroastrian

• TheZoroastrian calendarused regnal years since the reform byArdeshir I,but after the fall of theSassanid Empire,the ascension of the last Sassanid ruler,Yazdegerd III of Persia,crowned 16 June 632, continued to be used as the reference year, abbreviatedY.Z.or "Yazdegerd era".

Modern

Main article:List of calendars

Political

• The Republican Era of theFrench Republican Calendarwas dated from 22 September 1792, the day of the proclamation of theFrench First Republic.It was used in Revolutionary France from 24 October 1793 (on the Gregorian calendar) to 31 December 1805.
• ThePositivist calendarof 1844 takes 1789 as its epoch.
• TheRepublican erais used by theRepublic of China(now usually known as "Taiwan" ) since 1912, which is the first year of the republic. Coincidentally, this is the same as theJuche eraused inNorth Korea,the year of the birth of its founderKim Il-Sung.
• TheEra Fascista'Fascist Era' was instituted by theItalian Fascistsand usedRoman numeralsto denote the number of years since theMarch on Romein 1922. Therefore, 1934, for example, was XII E.F. (era fascista). This era was abolished with the fall of fascism in Italy on 25 July 1943, but restored in the northern part of the country during theItalian Social Republic.The Gregorian calendar remained in simultaneous use and a double numbering was adopted: the year of theCommon erawas presented in Arabic numerals and the year of the fascist era in Roman numerals. The year of the Fascist calendar began on 29 October, so, for example, 27 October 1933 was XI E.F. but 30 October 1933 was XII E.F.
• China traditionally reckoned by the regnal year of its emperors, seeChinese era name.Most Chinese do not assign numbers to the years of theChinese calendar,but the few who do, like expatriate Chinese, use a continuous count of years from the reign of the legendaryYellow Emperor,using 2698 BC as year 1. Western writers begin this count at either 2637 BC or 2697 BC (seeChinese calendar). Thus, the Chinese years 4637, 4697, or 4698 began in early 2000.
• In Korea, from 1952 until 1961 years were numbered viaDangiyears, where 2333 BC was regarded as the first such year.
• TheAssyrian calendar,introduced in the 1950s, has its era fixed at 4750 BC.
• TheJapanese calendardates from the accession of the currentEmperor of Japan.The current emperor took the throne in May 2019, which became Reiwa 1, and which was until then Heisei 31.
• TheUnited Statesgovernment sometimes uses a calendar of the era of itsIndependence,fixed on 4 July 1776, together with theAnno Dominicivil calendar. For instance, itsConstitutionis dated "the Seventeenth Day of September in the Year of our Lord one thousand seven hundred and Eighty seven and of the Independence of the United States of America the Twelfth."Presidential proclamationsare also dated in this way.

Religious

• A.D.– "AfterDianetics".InScientology,years are numbered relative to the first publication of the bookDianetics: The Modern Science of Mental Health(1950).
• Y.O.L.D.– In theDiscordian calendar,the standard designation for the year number is YOLD (Year ofOur Lady of Discord). The calendar begins counting from 1 January 1166 BC in theDiscordianyear 0, ostensibly the date of origin of theCurse of Greyface.An alternate designation, A.D.D. has been occasionally seen (Anno Domina Discordia, a Latin translation of YOLD, but presumably also a play onattention deficit disorder).
• e.v. –Era vulgaris.(From Latin, meaning "common era", usually stylized in lowercase.) Used by some followers ofAleister Crowleyto designate the era from theThelemiccalendar which is used by some Thelemites to designate a number of years since Crowley's inauguration of the so-calledAeon of Horus,which occurred on 20 March 1904, and coincides with both the Thelemic new year and a holiday known as the Equinox of the Gods. The abbreviation "A.N.", forAerae Novae( "New Era" in Latin), is also used for dates in the Thelemic calendar.

Practical

• B.P.– forBefore Present,specifically, the number ofradiocarbonyears before 1950.
• Julian day number– for counting days, not years, its era fixed at noon 1 January, 4713 BC in theproleptic Julian calendar.This equals 24 November, 4714 BC in theproleptic Gregorian calendar.From noon of this day to noon of the next day was day 0. Multiples of 7 are Mondays. Negative values can also be used. Apart from the choice of the zero point and name, this Julian day and Julian date are not related to theJulian calendar.It does not count years, so, strictly speaking, it has no era, but it does have anepoch.Today (noon-to-noon UTC) the value is 2460581.
• Unix time– for counting elapsed seconds since theUnix epochset at 00:00:00 or midnight UTC of 1 January 1970, though there are problems with Unix implementation ofCoordinated Universal Time(UTC).
• Holocene calendar

See also

• Calendar reform
• Common Era
• Julian day
• List of calendars