Era

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An era is a span of time defined for the purposes of chronology or historiography, as in the regnal eras in the history of a given monarchy, a calendar era used for a given calendar, or the geological eras defined for the history of Earth. [1]

Contents

Comparable terms are epoch, age, period, saeculum, aeon (Greek aion) [2] and Sanskrit yuga. [3]

Etymology

The word has been in use in English since 1615, [4] and is derived from Late Latin aera "an era or epoch from which time is reckoned," probably identical to Latin æra "counters used for calculation," plural of æs "brass, money". [5] [6]

The Latin word use in chronology seems to have begun in 5th century Visigothic Spain, where it appears in the History of Isidore of Seville, [7] and in later texts. The Spanish era is 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 the Battle 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

In chronology, 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 specific reference date (epoch), [12] which often marks the origin of a political state or cosmology, 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

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 the eon. [14] The Phanerozoic Eon, 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 66.038N/A
Mesozoic 252.1766.038
Paleozoic 542252.17

The older Proterozoic and Archean eons are also divided into eras. [18] [19]

Cosmological era

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

Calendar eras

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 a calculation of the age of the world, assuming it was created as described in the Book of Genesis. [21] In Jewish religious contexts one of the versions is still used, and many Eastern Orthodox religious 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 (AD also written CE ), counting the years since the birth of Jesus on traditional calculations, was always dominant. [24]

The Islamic calendar, which also has variants, counts years from the Hijra or emigration of the Islamic prophet Muhammad from Mecca to Medina, 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 the Second World War, the Japanese used the imperial year system (kōki), [27] counting from the year when the legendary Emperor Jimmu founded Japan, which occurred in 660 BC. [28]

Many Buddhist calendars count from the death of the Buddha, 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 the Thai solar calendar. [29]

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

Regnal eras

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 of regnal years is 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 of Romulus and Remus). [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.

In East 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, but Acts of Parliament were dated according to the years of the reign of the current monarch, so that "61 & 62 Vict c. 37" refers to the Local Government (Ireland) Act 1898 [34] passed in the session of Parliament in the 61st/62nd year of the reign of Queen Victoria. [35]

Historiography

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

See also

Related Research Articles

<i>Anno Domini</i> Western calendar era

The terms anno Domini (AD) and before Christ (BC) are used when designating years in the Julian and Gregorian calendars. The term anno Domini is Medieval Latin and means "in the year of the Lord" but is often presented using "our Lord" instead of "the Lord", taken from the full original phrase "anno Domini nostri Jesu Christi", which translates to "in the year of our Lord Jesus Christ". The form "BC" is specific to English, and equivalent abbreviations are used in other languages: the Latin form, rarely used in English, is Ante Christum natum (ACN) or Ante Christum (AC).

<i>Ab urbe condita</i> Ancient Roman calendar era

Ab urbe condita, or anno urbis conditae, abbreviated as AUC or AVC, expresses a date in years since 753 BC, the traditional founding of Rome. It is an expression used in antiquity and by classical historians to refer to a given year in Ancient Rome. In reference to the traditional year of the foundation of Rome, the year 1 BC would be written AUC 753, whereas AD 1 would be AUC 754. The foundation of the Roman Empire in 27 BC would be AUC 727. The current year AD 2023 would be AUC 2776.

<span class="mw-page-title-main">Calendar</span> System for organizing the days of year

A calendar is a system of organizing days. This is done by giving names to periods of time, typically days, weeks, months and years. A date is the designation of a single and specific day within such a system. A calendar is also a physical record of such a system. A calendar can also mean a list of planned events, such as a court calendar, or a partly or fully chronological list of documents, such as a calendar of wills.

Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar, the world's most widely used calendar era. Common Era and Before the Common Era are alternatives to the original Anno Domini (AD) and Before Christ (BC) notations used for the same calendar era. The two notation systems are numerically equivalent: "2023 CE" and "AD 2023" each describe the current year; "400 BCE" and "400 BC" are the same year.

<span class="mw-page-title-main">Chinese calendar</span> Lunisolar calendar from China

There are various types and subtypes of the Chinese calendar and horology, which over a millennium plus history has produced many variations. The topic of the Chinese calendar includes various traditional types of the Chinese calendar, of which particularly prominent are, identifying years, months, and days according to astronomical phenomena and calculations, with generally an especial effort to correlate the solar and lunar cycles experienced on earth—but which are known to mathematically require some degree of approximation. Typical features of early calendars include the use of the sexagenary cycle-based ganzhi system's repeating cycles of Heavenly Stems and Earthly Branches. The logic of the various permutations of the Chinese calendar has been based in considerations such as the technical from mathematics and astronomy, the philosophical considerations, and the political, and the resulting disparities between different calendars is significant and notable. Various similar calendar systems are also known from various regions or ethnic groups of Central Asia, South Asia, and other areas. Indeed, the Chinese calendar has influenced and been influenced by most parts of the world these days. One particularly popular feature is the Chinese zodiac. The Chinese calendar and horology includes multifaceted methods of computing years, eras, months, days and hours.

<span class="mw-page-title-main">Hebrew calendar</span> Lunisolar calendar used for Jewish religious observances

The Hebrew calendar, also called the Jewish calendar, is a lunisolar calendar used today for Jewish religious observance and as an official calendar of Israel. It determines the dates of Jewish holidays and other rituals, such as yahrzeits and the schedule of public Torah readings. In Israel, it is used for religious purposes, provides a time frame for agriculture, and is an official calendar for civil holidays alongside the Gregorian calendar.

<span class="mw-page-title-main">Islamic calendar</span> Lunar calendar used by Muslims to determine religious observances

The Hijri calendar, also known in English as the Muslim calendar and Islamic calendar, is a lunar calendar consisting of 12 lunar months in a year of 354 or 355 days. It is used to determine the proper days of Islamic holidays and rituals, such as the annual fasting and the annual season for the great pilgrimage. In almost all countries where the predominant religion is Islam, the civil calendar is the Gregorian calendar, with Syriac month-names used in the Levant and Mesopotamia but the religious calendar is the Hijri one.

<span class="mw-page-title-main">New moon</span> First lunar phase, the definition varies

In astronomy, the new moon is the first lunar phase, when the Moon and Sun have the same ecliptic longitude. At this phase, the lunar disk is not visible to the naked eye, except when it is silhouetted against the Sun during a solar eclipse.

<span class="mw-page-title-main">Year</span> Time of one planets orbit around a star

A year is the time taken for astronomical objects to complete one orbit. For example, a year on Earth is the time taken for Earth to revolve around the Sun. Generally, a year is taken to mean a calendar year, but the word is also used for periods loosely associated with the calendar or astronomical year, such as the seasonal year, the fiscal year, the academic year, etc. The term can also be used in reference to any long period or cycle, such as the Great Year.

The Julian day is the continuous count of days since the beginning of the Julian period, and is used primarily by astronomers, and in software for easily calculating elapsed days between two events.

In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured.

<span class="mw-page-title-main">Chronology</span> Science of arranging events in order of occurrence

Chronology is the science of arranging events in their order of occurrence in time. Consider, for example, the use of a timeline or sequence of events. It is also "the determination of the actual temporal sequence of past events".

A calendar era is the period of time elapsed since one epoch of a calendar and, if it exists, before the next one. For example, it is the year 2023 as per the Gregorian calendar, which numbers its years in the Western Christian era.

<i>Anno Mundi</i> Calendar era based on the biblical account of creation

Anno Mundi, abbreviated as AM or A.M., or Year After Creation, is a calendar era based on the biblical accounts of the creation of the world and subsequent history. Two such calendar eras have seen notable use historically:

A regnal year is a year of the reign of a sovereign, from the Latin regnum meaning kingdom, rule. Regnal years considered the date as an ordinal, not a cardinal number. For example, a monarch could have a first year of rule, a second year of rule, a third year of rule, and so on, but not a zeroth year of rule.

The Islamic New Year, also called the Hijri New Year, is the day that marks the beginning of a new lunar Hijri year, and is the day on which the year count is incremented. The first day of the Islamic year is observed by most Muslims on the first day of the month of Muharram. The epoch of the Islamic era was set as the year of the emigration of Muhammad and his followers from Mecca to Medina, known as the Hijrah, which equates to 622 CE in the Gregorian calendar. All religious duties, such as prayer, fasting in the month of Ramadan, and pilgrimage, and the dates of significant events, such as celebration of holy nights and festivals, are calculated according to the Islamic calendar.

The Hijri year or era is the era used in the Islamic lunar calendar. It begins its count from the Islamic New Year in which Muhammad and his followers migrated from Mecca to Yathrib in 622 CE. This event, known as the Hijrah, is commemorated in Islam for its role in the founding of the first Muslim community (ummah).

<span class="mw-page-title-main">Unit of time</span> Measurement unit for time

A unit of time is any particular time interval, used as a standard way of measuring or expressing duration. The base unit of time in the International System of Units (SI), and by extension most of the Western world, is the second, defined as about 9 billion oscillations of the caesium atom. The exact modern SI definition is "[The second] is defined by taking the fixed numerical value of the cesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the cesium 133 atom, to be 9 192 631 770 when expressed in the unit Hz, which is equal to s−1."

The Holocene calendar, also known as the Holocene Era or Human Era (HE), is a year numbering system that adds exactly 10,000 years to the currently dominant numbering scheme, placing its first year near the beginning of the Holocene geological epoch and the Neolithic Revolution, when humans shifted from a hunter-gatherer lifestyle to agriculture and fixed settlements. The current year by the Gregorian calendar, AD 2023, is 12023 HE in the Holocene calendar. The HE scheme was first proposed by Cesare Emiliani in 1993, though similar proposals to start a new calendar at the same date had been put forward decades earlier.

<span class="mw-page-title-main">Solar Hijri calendar</span> Official calendar of Iran

The Solar Hijri calendar is a solar calendar and one of the various Iranian calendars. It begins on the March equinox as determined by the astronomical calculation for the Iran Standard Time meridian and has years of 365 or 366 days. It is the modern principal calendar in Iran and is sometimes also called the Shamsi calendar and Khorshidi calendar. It is abbreviated as SH, HS or, by analogy with AH, AHSh.

References

  1. ↑ "Era | definition in the Cambridge English Dictionary". Cambridge Dictionary. Retrieved 11 December 2023.
  2. ↑ "Thesaurus.com - The world's favorite online thesaurus!". Thesaurus.com. 6 December 2023. Retrieved 11 December 2023.
  3. ↑ "Yuga". Dictionary.com Unabridged (Online). n.d. Retrieved 11 December 2023.
  4. ↑ "Time Traveler by Merriam-Webster: Words from 1615". www.merriam-webster.com. Retrieved 11 December 2023.
  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. JSTOR   593870.
  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. ISBN   978-0-415-93918-8.
  10. ↑ "Actium, 31 BC: the beginning of the end for Mark Antony and Cleopatra". HistoryExtra. Retrieved 11 December 2023.
  11. ↑ "Definition of EPOCH". www.merriam-webster.com. 22 November 2023. Retrieved 11 December 2023.
  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. ISBN   978-1-891389-85-6.
  13. 1 2 "The Geological Society of London - How are Geological Periods Determined?". www.geolsoc.org.uk. Retrieved 11 December 2023.
  14. ↑ Martin Harweit (1991). Astrophysical Concepts (2nd ed.). Springer-Verlag. ISBN   3-540-96683-8. p. 4.
  15. ↑ Short, N.M. (2009). "Geologic Time" Archived 2005-04-18 at the Wayback Machine in Remote Sensing Tutorial Archived 2009-10-27 at the Wayback 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 from the original on 30 May 2014.
  18. ↑ "Proterozoic Eon | Oxygen Crisis, Animals, & Facts | Britannica". www.britannica.com. Retrieved 11 December 2023.
  19. ↑ "Archean Eon | Atmosphere, Timeline, and Facts | Britannica". www.britannica.com. Retrieved 11 December 2023.
  20. ↑ "Big Bang Timeline- The Big Bang and the Big Crunch - The Physics of the Universe". www.physicsoftheuniverse.com. Retrieved 11 December 2023.
  21. ↑ "Anno mundi | Jewish Calendar, History & Origins | Britannica". www.britannica.com. Retrieved 11 December 2023.
  22. ↑ "Hebrew Date Converter - September 28, 2011 after sunset / 1st of Tishrei, 5772". www.hebcal.com. Retrieved 11 December 2023.
  23. ↑ "Hebrew Date Converter - September 16, 2012 after sunset / 1st of Tishrei, 5773". www.hebcal.com. Retrieved 11 December 2023.
  24. ↑ "Chronology - Christian History, Dates, Events | Britannica". www.britannica.com. Retrieved 11 December 2023.
  25. ↑ "Islamic calendar | Months, Definition, & Facts | Britannica". www.britannica.com. 14 November 2023. Retrieved 11 December 2023.
  26. ↑ "Hijri to Gregorian Date Converter - Islamic Date Converter". IslamicFinder. Retrieved 11 December 2023.
  27. ↑ Louis-Frédéric (2002). Japan Encyclopedia. Harvard University Press. ISBN   978-0-674-01753-5.
  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. 1 2 "Calendar systems and their role in patent documentation | Epo.org". www.epo.org. Retrieved 11 December 2023.
  30. ↑ Denis C. Feeney, Caesar's Calendar, University of California Press, Berkeley 2007, p. 139.
  31. 1 2 Wiseman, Timothy Peter (1995). Remus: A Roman Myth. Cambridge University Press. ISBN   978-0-521-48366-7.
  32. ↑ "Regnal Years - The University of Nottingham". www.nottingham.ac.uk. Retrieved 11 December 2023.
  33. ↑ "Calendar systems and their role in patent documentation | Epo.org". www.epo.org. Retrieved 11 December 2023.
  34. ↑ Beckett, J C (1966). The Making of Modern Ireland 1603 – 1923. London: Faber & Faber. p. 406. ISBN   0-571-09267-5.
  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. Retrieved 11 December 2023.
  37. ↑ "Big Bands and the Swing Era". Acoustic Music. Retrieved 11 December 2023.
  38. ↑ "Disco | Origins, Genres & Cultural Impact | Britannica". www.britannica.com. 9 December 2023. Retrieved 11 December 2023.

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