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Era

For other uses, seeEra (disambiguation).
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Anerais a span of time defined for the purposes ofchronologyorhistoriography,as in theregnal erasin the history of a given monarchy, acalendar eraused for a givencalendar,or thegeological erasdefined for thehistory of Earth.[1]

Comparable terms areepoch,age,period,saeculum,aeon(Greekaion)[2]and Sanskrityuga.[3]

Etymology

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The word has been in use in English since 1615,[4]and is derived fromLate Latinaera"an era or epoch from which time is reckoned," probably identical to Latinæra"counters used for calculation," plural ofæs"brass, money".[5][6]

The Latin word use in chronology seems to have begun in 5th centuryVisigothicSpain, where it appears in theHistoryofIsidore of Seville,[7]and in later texts. TheSpanish erais calculated from 38 BC, Before Christ,[8][9]perhaps because of a tax (cfr.indiction) levied in that year, or due to a miscalculation of theBattle of Actium,which occurred in 31 BC.[10]

Like epoch, "era" in English originally meant "the starting point of an age"; the meaning "system of chronological notation" is c. 1646; that of "historical period" is 1741.[11]

Use in chronology

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Inchronology,an "era" is the highest level for the organization of the measurement of time. A "calendar era"indicates a span of many years which are numbered beginning at a specificreference date (epoch),[12]which often marks the origin of a political state orcosmology,dynasty, ruler, the birth of a leader, or another significant historical or mythological event;[13]it is generally called after its focus accordingly as in "Victorian era".

Geological era

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Main article:Era (geology)

In large-scale natural science, there is need for another time perspective, independent from human activity, and indeed spanning a far longer period (mainly prehistoric), where "geologic era"refers to well-defined time spans.[13] The next-larger division of geologic time is theeon.[14]ThePhanerozoicEon, for example, is subdivided into eras.[15]There are currently three eras defined in the Phanerozoic; the following table lists them from youngest to oldest (BP is an abbreviation for "before present").

Era[16][17] Beginning (millions of years BP) End (millions of years BP)
Cenozoic 66.038 N/A
Mesozoic 252.17 66.038
Paleozoic 542 252.17

The olderProterozoicandArcheaneons are also divided into eras.[18][19]

Cosmological era

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For periods in thehistory of the universe,the term "epoch"is typically preferred, but" era "is used e.g. of the"Stelliferous Era".[20]

Calendar eras

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Main article:Calendar era

Calendar eras count the years since a particular date (epoch), often one with religious significance.Anno mundi(year of the world) refers to a group of calendar eras based on acalculation of the age of the world,assuming it was created as described in theBook of Genesis.[21]In Jewish religious contexts one of the versions is still used, and manyEastern Orthodoxreligious calendars used another version until 1728. Hebrew year 5772 AM began at sunset on 28 September 2011[22]and ended on 16 September 2012.[23]In the Western church,Anno Domini(ADalso writtenCE), counting the years since the birth of Jesus on traditional calculations, was always dominant.[24]

TheIslamic calendar,which also has variants, counts years from theHijraor emigration of the Islamic prophetMuhammadfromMeccatoMedina,which occurred in 622 AD.[25]The Islamic year is some days shorter than 365; January 2012 fell in 1433 AH ( "After Hijra" ).[26]

For a time ranging from 1872 to theSecond World War,the Japanese used the imperial year system (kōki),[27]counting from the year when the legendaryEmperor Jimmufounded Japan, which occurred in 660 BC.[28]

ManyBuddhist calendarscount from the death of theBuddha,which according to the most commonly used calculations was in 545–543 BCE or 483 BCE.[29]Dates are given as "BE" for "Buddhist Era"; 2000 AD was 2543 BE in theThai solar calendar.[29]

Other calendar eras of the past counted from political events, such as theSeleucid era[30]and the Ancient Romanab urbe condita( "AUC" ), counting from the foundation of the city.[31]

Regnal eras

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Main article:Regnal year

The word era also denotes the units used under a different, more arbitrary system where time is not represented as an endless continuum with a single reference year, but each unit starts counting from one again as if time starts again.[32]The use ofregnal yearsis a rather impractical system, and a challenge for historians if a single piece of the historical chronology is missing, and often reflects the preponderance in public life of an absolute ruler in many ancient cultures. Such traditions sometimes outlive the political power of the throne, and may even be based on mythological events or rulers who may not have existed (for example Rome numbering from the rule ofRomulusandRemus).[31]In a manner of speaking the use of the supposed date of the birth of Christ as a base year is a form of an era.

InEast Asia,each emperor's reign may be subdivided into several reign periods, each being treated as a new era.[33]The name of each was a motto or slogan chosen by the emperor. Different East Asian countries utilized slightly different systems, notably:

A similar practice survived in the United Kingdom until quite recently, but only for formal official writings: in daily life the ordinary year A.D. has been used for a long time, butActs of Parliamentwere dated according to the years of the reign of the currentmonarch,so that "61 & 62 Vict c. 37" refers to theLocal Government (Ireland) Act 1898[34]passed in the session ofParliamentin the 61st/62nd year of the reign ofQueen Victoria.[35]

Historiography

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"Era" can be used to refer to well-defined periods in historiography, such as theRoman era,Elizabethan era,Victorian era,etc.[36] Use of the term for more recent periods or topical history might includeSoviet era,and "musical eras" in the history of modernpopular music,such as the "big band era","disco era",etc.[37][38]

See also

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References

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  1. ^"Era | definition in the Cambridge English Dictionary".Cambridge Dictionary.Retrieved11 December2023.
  2. ^"Thesaurus - The world's favorite online thesaurus!".Thesaurus.6 December 2023.Retrieved11 December2023.
  3. ^"Yuga".Dictionary Unabridged(Online). n.d.Retrieved11 December2023.
  4. ^"Time Traveler by Merriam-Webster: Words from 1615".merriam-webster.Retrieved11 December2023.
  5. ^Peón, Baltasar (1863).Estudios de cronología universal(in Spanish). Imprenta Nacional.
  6. ^Levi Della Vida, Giorgio(1943). "The 'Bronze Era' in Moslem Spain".Journal of the American Oriental Society.63(3): 183–191.doi:10.2307/593870.JSTOR593870.
  7. ^Hispalensis, Isidorus (1773).Isidori Hispalensis Historia de regibus Gothorum, Vandalorum et Suevorum(in Latin).
  8. ^Cheney, Carl D.; Jones, Michael (2000).A Handbook of Dates: For Students of British History(Rev. ed.). Cambridge University Press. p. 2.
  9. ^Roth, Norman (2003). "Calendar". In Gerli, E. Michael (ed.).Medieval Iberia: An Encyclopedia.Routledge. p. 190.ISBN978-0-415-93918-8.
  10. ^"Actium, 31 BC: the beginning of the end for Mark Antony and Cleopatra".HistoryExtra.Retrieved11 December2023.
  11. ^"Definition of EPOCH".merriam-webster.22 November 2023.Retrieved11 December2023.
  12. ^Richards, E. G. (2013). "Calendars". In Urban, Sean E.; Seidelmann, P. Kenneth (eds.).Explanatory Supplement to the Astronomical Almanac(3 ed.). Mill Valley, CA: Univ Science Books.ISBN978-1-891389-85-6.
  13. ^ab"The Geological Society of London - How are Geological Periods Determined?".geolsoc.org.uk.Retrieved11 December2023.
  14. ^Martin Harweit (1991).Astrophysical Concepts(2nd ed.). Springer-Verlag.ISBN3-540-96683-8.p. 4.
  15. ^Short, N.M. (2009)."Geologic Time"Archived2005-04-18 at theWayback MachineinRemote Sensing TutorialArchived2009-10-27 at theWayback Machine.NASA.
  16. ^Lide, D. R. (1990).Handbook of Chemistry and Physics.Boca Raton: CRC Press. pp. 14–16.
  17. ^"International Stratigraphic Chart".International Commission on Stratigraphy. Archived fromthe originalon 30 May 2014.
  18. ^"Proterozoic Eon | Oxygen Crisis, Animals, & Facts | Britannica".britannica.Retrieved11 December2023.
  19. ^"Archean Eon | Atmosphere, Timeline, and Facts | Britannica".britannica.Retrieved11 December2023.
  20. ^"Big Bang Timeline- The Big Bang and the Big Crunch - The Physics of the Universe".physicsoftheuniverse.Retrieved11 December2023.
  21. ^"Anno mundi | Jewish Calendar, History & Origins | Britannica".britannica.Retrieved11 December2023.
  22. ^"Hebrew Date Converter - September 28, 2011 after sunset / 1st of Tishrei, 5772".hebcal.Retrieved11 December2023.
  23. ^"Hebrew Date Converter - September 16, 2012 after sunset / 1st of Tishrei, 5773".hebcal.Retrieved11 December2023.
  24. ^"Chronology - Christian History, Dates, Events | Britannica".britannica.Retrieved11 December2023.
  25. ^"Islamic calendar | Months, Definition, & Facts | Britannica".britannica.14 November 2023.Retrieved11 December2023.
  26. ^"Hijri to Gregorian Date Converter - Islamic Date Converter".IslamicFinder.Retrieved11 December2023.
  27. ^Louis-Frédéric (2002).Japan Encyclopedia.Harvard University Press.ISBN978-0-674-01753-5.
  28. ^Gubbins, John Harrington. (1922).The Making of Modern Japan,p. 71;Mossman, Samuel. (1873).New Japan, the Land of the Rising Sun,p. 462.
  29. ^ab"Calendar systems and their role in patent documentation | Epo.org".epo.org.Retrieved11 December2023.
  30. ^Denis C. Feeney,Caesar's Calendar,University of California Press,Berkeley 2007, p. 139.
  31. ^abWiseman, Timothy Peter (1995).Remus: A Roman Myth.Cambridge University Press.ISBN978-0-521-48366-7.
  32. ^"Regnal Years - The University of Nottingham".nottingham.ac.uk.Retrieved11 December2023.
  33. ^"Calendar systems and their role in patent documentation | Epo.org".epo.org.Retrieved11 December2023.
  34. ^Beckett, J C (1966).The Making of Modern Ireland 1603 – 1923.London: Faber & Faber. p. 406.ISBN0-571-09267-5.
  35. ^"Chapter Five: Table of regnal year of English Sovereigns".Sweet & Maxwell's Guide to Law Reports and Statutes(Fourth ed.). London: Sweet & Maxwell's Guide. 1962. pp. 20–33.
  36. ^"Historiography | NMU Writing Center".nmu.edu.Retrieved11 December2023.
  37. ^"Big Bands and the Swing Era".Acoustic Music.Retrieved11 December2023.
  38. ^"Disco | Origins, Genres & Cultural Impact | Britannica".britannica.9 December 2023.Retrieved11 December2023.

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