Anno Domini

{{short description|Western calendar era}}
{{Other uses}}
{{redirect-multi|2|AD|Christian era}}
{{italic title}}
{{Use dmy dates|date=January 2021}}

[[File:Austria Klagenfurt Dome 12.jpg|thumb|''Anno Domini'' inscription at [[Klagenfurt Cathedral]], Austria]]

The terms '''{{lang|la|anno Domini}}''' ('''AD''') and '''before Christ''' ('''BC'''){{efn|The words ''anno'' and ''before'' are often capitalized, but this is considered incorrect by some and either not mentioned in major dictionaries or only listed as an alternative. {{Citation needed|date=February 2024}}}} are used when designating years in the [[Julian calendar|Julian]] and [[Gregorian calendar]]s. The term {{Lang|la-x-medieval|anno Domini}} is [[Medieval Latin]] and means "in the year of the Lord"<ref>{{cite encyclopedia |url = http://www.m-w.com/dictionary/Anno%20Domini |title=Anno Domini |encyclopedia=[[Merriam Webster]] Online Dictionary |quote=Etymology: Medieval Latin, in the year of the Lord |access-date=4 October 2011 }}</ref> but is often presented using "our Lord" instead of "the Lord",<ref>{{cite web |url = http://www.etymonline.com/index.php?term=Anno+Domini |title= Anno Domini |website=Online Etymology Dictionary |access-date=4 October 2011 }}</ref><ref>{{harvnb|Blackburn|Holford-Strevens|2003|p=782}} "since AD stands for ''anno Domini'', 'in the year of (Our) Lord{{'"}}</ref> 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 (language)|English]], and equivalent abbreviations are used in other languages: the [[Latin (language)|Latin]] form, rarely used in English, is {{lang|la|[[Ante Christum natum]]}} (ACN) or {{lang|la|[[Ante Christum]]}} (AC).

This [[calendar era]] is based on the traditionally reckoned year of the [[annunciation|conception]] or [[Nativity of Jesus|birth]] of Jesus, ''AD'' counting years from the start of this [[epoch (date reference)|epoch]] and ''BC'' denoting years before the start of the era. There is no [[year zero]] in this scheme; thus the year [[AD 1]] immediately follows the year [[1 BC]]. This dating system was devised in 525 by [[Dionysius Exiguus]] but was not widely used until the 9th century.<ref name="Teresi1997">{{cite journal |url = https://www.theatlantic.com/past/docs/issues/97jul/zero.htm |author-link=Dick Teresi |first=Dick |last=Teresi |title=Zero |journal=[[The Atlantic]] |date=July 1997 |url-access=subscription |url-status=live |archive-url=https://web.archive.org/web/20220605092148/https://www.theatlantic.com/magazine/archive/1997/07/zero/376900/ |archive-date= Jun 5, 2022 }}</ref>{{sfn|Blackburn|Holford-Strevens|2003|pp=778–79}}

Terminology that is viewed by some as being more neutral and inclusive of non-Christian people is to call this the [[Common Era]] (abbreviated as CE), with the preceding years referred to as Before the Common Era (BCE). [[Astronomical year numbering]] and [[ISO 8601]] avoid words or abbreviations related to Christianity, but use the same numbers for AD years (but not for BC years in the case of astronomical years; e.g., 1 BC is year 0, 45 BC is year −44).

==Usage==
Traditionally, English follows Latin usage by placing the "AD" abbreviation before the year number, though it is also found after the year.<ref>''Chicago Manual of Style'' 2010, pp. 476–7; Goldstein 2007, p. 6.</ref> In contrast, "BC" is always placed after the year number (for example: AD&nbsp;70, but 70&nbsp;BC), which preserves syntactic order. The abbreviation "AD" is also widely used after the number of a century or [[millennium]], as in "fourth century AD" or "second millennium AD" (although conservative usage formerly rejected such expressions).<ref>''Chicago Manual of Style'', 1993, p. 304.</ref> Since "BC" is the English abbreviation for ''Before Christ'', it is sometimes incorrectly concluded that AD means ''After Death'' (i.e., after the death of Jesus), which would mean that the approximately 33 years commonly associated with the [[life of Jesus]] would be included in neither the BC nor the AD time scales.{{sfn |Ryan |2000 |p = 15}}

== History ==
{{see also|Date of birth of Jesus|Nativity of Jesus#Date of birth|Chronology of Jesus#Year of Jesus' birth}}

The ''Anno Domini'' dating system was devised in 525 by [[Dionysius Exiguus]] to enumerate years in [[Dionysius Exiguus' Easter table|his Easter table]]. His system was to replace the [[Era of Martyrs|Diocletian era]] that had been used in [[Easter table#History|older Easter tables]], as he did not wish to continue the memory of a tyrant who [[Diocletianic Persecution|persecuted Christians]].{{sfn|Blackburn|Holford-Strevens|2003|p=767}} The last year of the old table, Diocletian [[Era of the Martyrs|Anno Martyrium]] 247, was immediately followed by the first year of his table, Anno Domini 532. When Dionysius devised his table, [[Julian calendar]] years were identified by naming the [[Roman consul|consuls]] who held office that year— Dionysius himself stated that the "present year" was "the consulship of [[Flavius Anicius Probus Iunior|Probus Junior]]", which was 525 years "since the incarnation of our Lord Jesus Christ".<ref>[https://web.archive.org/web/20161226031734/http://hbar.phys.msu.ru/gorm/chrono/paschata.htm Nineteen year cycle of Dionysius] Introduction and First Argumentum.</ref> Thus, Dionysius implied that [[Incarnation (Christianity)|Jesus' incarnation]] occurred 525 years earlier, without stating the specific year during which his birth or conception occurred. "However, nowhere in his exposition of his table does Dionysius relate his epoch to any other dating system, whether consulate, [[Olympiad]], [[Anno Mundi|year of the world]], or [[regnal year]] of Augustus; much less does he explain or justify the underlying date."{{sfn|Blackburn|Holford-Strevens|2003|p=778}}

[[Bonnie J. Blackburn]] and [[Leofranc Holford-Strevens]] briefly present arguments for 2 BC, 1 BC, or AD 1 as the year Dionysius intended for the [[Nativity of Jesus|Nativity]] or [[Incarnation (Christianity)|incarnation]]. Among the sources of confusion are:{{sfn|Blackburn|Holford-Strevens|2003|pp=778–79}}
* In modern times, [[incarnation]] is synonymous with the conception, but some ancient writers, such as [[Bede]], considered incarnation to be synonymous with the Nativity.
* The civil or consular year began on 1 January, but the Diocletian year began on 29 August (30 August in the year before a Julian leap year).
* There were inaccuracies in the lists of consuls.
* There were confused summations of emperors' regnal years.

It is not known how Dionysius established the year of Jesus's birth. One major theory is that Dionysius based his calculation on the [[Gospel of Luke]], which states that Jesus was "about thirty years old" shortly after "the fifteenth year of the reign of Tiberius Caesar", and hence subtracted thirty years from that date, or that Dionysius counted back 532 years from the first year of his new table.<ref>{{cite journal|last=Teres|first=Gustav|date=October 1984|title=Time computations and Dionysius Exiguus|journal=Journal for the History of Astronomy|volume=15|issue=3|pages=177–88|bibcode=1984JHA....15..177T |bibcode-access=free |doi=10.1177/002182868401500302|s2cid=117094612}}</ref><ref>Tøndering, Claus, "[http://www.tondering.dk/claus/cal/years.php The Calendar FAQ: Counting years]". {{Webarchive|url=https://web.archive.org/web/20210924142100/https://www.tondering.dk/claus/cal/years.php |date=24 September 2021 }}.</ref><ref name=Moss>{{cite book |url = https://books.google.com/books?id=0umDqPOf2L8C&pg=PA347 |publisher=Oxford University Press |last=Mosshammer|first=Alden A|title=The Easter Computus and the Origins of the Christian Era|location=Oxford|year=2009|pages=254, 270, 328, 333, 345–47|isbn=978-0191562365}}</ref> This method was probably the one used by ancient historians such as [[Tertullian]], [[Eusebius]] or [[Epiphanius of Salamis|Epiphanius]], all of whom agree that Jesus was born in 2 BC,<ref name=":12">{{Cite book |last=Beyer |first=David |title=Chronos, Kairos, Christos II: Chronological, Nativity, and Religious Studies in Memory of Ray Summers |date=1998 |publisher=Mercer University Press |isbn=978-0-86554-582-3 |editor-last=Vardaman |editor-first=Jerry |pages=85–96 |chapter=Josephus Reexamined: Unraveling the Twenty-Second Year of Tiberius |chapter-url=https://books.google.com/books?id=mWnYvI5RdLMC&pg=PA93}}</ref> probably following this statement of Jesus' age (i.e. subtracting thirty years from AD 29).<ref>{{Cite book |last=Finegan |first=Jack |url=https://books.google.com/books?id=tUzSEAAAQBAJ&pg=PA345 |title=The Handbook of Biblical Chronology |date=2015 |publisher=Hendrickson Publishers |isbn=978-1-61970-641-5 |pages=345 |language=}}</ref> Alternatively, Dionysius may have used an earlier unknown source. The [[Chronograph of 354]] states that Jesus was born during the consulship of [[Gaius Caesar|Caesar]] and [[Lucius Aemilius Paullus (consul 1)|Paullus]] (AD 1), but the logic behind this is also unknown.<ref name=":2">{{cite book |last=Mosshammer |first=Alden A |url=https://books.google.com/books?id=0umDqPOf2L8C&pg=PA347 |publisher=Oxford University Press |title=The Easter Computus and the Origins of the Christian Era |year=2009 |isbn=978-0191562365 |location=Oxford |pages=319–56}}</ref>

It has also been speculated by Georges Declercq<ref name=":0">Declercq, Georges(2000). "Anno Domini. The Origins of the Christian Era" Turnhout, Belgium, {{page needed|date=March 2021}}</ref> that Dionysius' desire to replace Diocletian years with a calendar based on the incarnation of Christ was intended to prevent people from believing the imminent [[Eschatology|end of the world]]. At the time, it was believed by some that the [[resurrection of the dead]] and end of the world would occur 500 years after the birth of Jesus. The old ''[[Anno Mundi]]'' calendar theoretically commenced with the [[Dating creation|creation of the world]] based on information in the [[Old Testament]]. It was believed that, based on the ''Anno Mundi'' calendar, Jesus was born in the year 5500 (5500 years after the world was created) with the year 6000 of the ''Anno Mundi'' calendar marking the end of the world.<ref>Wallraff, Martin: Julius Africanus und die Christliche Weltchronik. Walter de Gruyter, 2006</ref><ref name=Moss/> ''Anno Mundi'' 6000 (approximately AD 500) was thus equated with the end of the world<ref name=":0" /> but this date had already passed in the time of Dionysius.
The "''Historia Brittonum''" attributed to Nennius written in the 9th century makes extensive use of the Anno Passionis (AP) dating system which was in common use as well as the newer AD dating system. The AP dating system took its start from 'The Year of The Passion'. It is generally accepted by experts there is a 27-year difference between AP and AD reference.<ref>Halsall, Guy (2013). ''Worlds of Arthur: Facts & Fictions of The Dark Ages''. Oxford University Press, pp 194 - 200</ref>

The date of birth of Jesus of Nazareth is not stated in the gospels or in any secular text, but most scholars assume a date of birth between 6 BC and 4 BC.<ref name="JDG324">{{Cite book |last=Dunn |first=James DG |url=https://archive.org/details/jesusrememberedc00jame |title=Jesus Remembered |publisher=Eerdmans Publishing |year=2003 |page=[https://archive.org/details/jesusrememberedc00jame/page/n342 324] |url-access=limited}}</ref> The historical evidence is too fragmentary to allow a definitive dating,<ref>Doggett 1992, p579: "Although scholars generally believe that Christ was born some years before AD 1, the historical evidence is too sketchy to allow a definitive dating".</ref> but the date is estimated through two different approaches—one by analyzing references to known historical events mentioned in the Nativity accounts in the Gospels of Luke and Matthew and the second by working backwards from the estimation of the start of the [[ministry of Jesus]].<ref name="ChronosPaul">[[Paul L. Maier]] "The Date of the Nativity and Chronology of Jesus" in ''Chronos, kairos, Christos: nativity and chronological studies'' by Jerry Vardaman, Edwin M. Yamauchi 1989 {{ISBN|0-931464-50-1}} pp. 113–29</ref><ref name="Niswonger121">''New Testament History'' by Richard L. Niswonger 1992 {{ISBN|0-310-31201-9}} pp. 121–24</ref>

=== Popularization ===
The [[Anglo-Saxons|Anglo-Saxon]] historian [[Bede]], who was familiar with the work of Dionysius Exiguus, used ''Anno Domini'' dating in his ''[[Ecclesiastical History of the English People]]'', which he completed in AD 731. In the ''History'' he also used the [[Latin]] phrase ''ante [...] incarnationis dominicae tempus anno sexagesimo'' ("in the sixtieth year before the time of the Lord's incarnation"), which is equivalent to the English "before Christ", to identify years before the first year of this era.<ref>Bede 731, Book 1, Chapter 2, first sentence.</ref> Both Dionysius and Bede regarded ''Anno Domini'' as beginning at the incarnation of [[Jesus Christ]], but "the distinction between Incarnation and Nativity was not drawn until the late 9th century, when in some places the Incarnation epoch was identified with Christ's conception, i. e., the [[Annunciation]] on March 25" ("Annunciation style" dating).{{sfn|Blackburn|Holford-Strevens|2003|p=881}}

[[File:Charlemagne Agostino Cornacchini Vatican 2.jpg|thumb|right|Statue of [[Charlemagne]] by [[Agostino Cornacchini]] (1725), at [[St. Peter's Basilica]], Vatican City. Charlemagne promoted the usage of the ''Anno Domini'' epoch throughout the [[Carolingian Empire]].]]
On the continent of Europe, ''Anno Domini'' was introduced as the era of choice of the [[Carolingian Renaissance]] by the English cleric and scholar [[Alcuin]] in the late eighth century. Its endorsement by Emperor [[Charlemagne]] and [[List of Frankish Kings#Carolingian dynasty|his successors]] popularizing the use of the epoch and spreading it throughout the [[Carolingian Empire]] ultimately lies at the core of the system's prevalence. According to the [[Catholic Encyclopedia]], popes continued to date documents according to [[regnal years]] for some time, but usage of AD gradually became more common in Catholic countries from the 11th to the 14th centuries.<ref name=CathEncy>Patrick, 1908</ref> In 1422, [[Portugal]] became the last Western European country to [[Spanish era|switch to]] the system begun by Dionysius.<ref name="CathEncy-Chron">
{{cite book
|chapter-url = http://www.newadvent.org/cathen/03738a.htm
|chapter=General Chronology
|title=New Advent Catholic Encyclopedia
|year=1908
|volume=III
|publisher=[[Robert Appleton Company]] |location=New York
|access-date=25 October 2011 }}
</ref> [[Eastern Orthodox]] countries only began to adopt AD instead of the [[Byzantine calendar]] in 1700 when Russia did so, with others adopting it in the 19th and 20th centuries.

Although ''Anno Domini'' was in widespread use by the 9th century, the term "Before Christ" (or its equivalent) did not become common until much later. Bede used the expression ''"anno [...] ante incarnationem Dominicam"'' (in the year before the incarnation of the Lord) twice. ''"Anno ante Christi nativitatem"'' (in the year before the birth of Christ) is found in 1474 in a work by a German monk.{{efn|[[Werner Rolevinck]] in ''Fasciculus temporum'' (1474) used ''Anno ante xpi nativitatem'' (in the year before the birth of Christ) for all years between [[Genesis creation narrative|creation]] and Jesus. "xpi" comes from the [[Greek language|Greek]] χρ (''chr'') in visually Latin letters, together with the Latin ending -i, thus abbreviating ''Christi'' ("of Christ"). This phrase appears upside down in the centre of [[recto]] folios (right hand pages). From Jesus to [[Pope Sixtus IV]] he usually used ''Anno Christi'' or its abbreviated form ''Anno xpi'' (on [[verso]] folios—left hand pages). He used ''Anno mundi'' alongside all of these terms for all years.}} In 1627, the French [[Jesuit]] theologian [[Denis Pétau]] (Dionysius Petavius in Latin), with his work ''De doctrina temporum'', popularized the usage ''ante Christum'' (Latin for "Before Christ") to mark years prior to AD.<ref>
{{cite book
|url = https://books.google.com/books?id=fsni_qV-FJoC&q=1627&pg=PA111
|title=Marking time: the epic quest to invent the perfect calendar
|first=Duncan |last=Steel |author-link=Duncan Steel
|page=114
|access-date=1 June 2010
|isbn=978-0-471-29827-4
|year=2000
|publisher=Wiley
}}</ref><ref>
{{cite book
|url = https://books.google.com/books?id=A6nrL1XxpGYC&q=petau%20%22ante%20Christum%22&pg=PA33
|title=Measuring time, making history
|first=Lynn Avery |last=Hunt
|year=2008
|page=33
|publisher=Central European University Press
|access-date=1 June 2010
|isbn=978-963-9776-14-2
}}</ref><ref>
{{cite book
|url = https://books.google.com/books?id=RRv0_NEpl-oC&q=ante%20Christum&pg=PA46
|title=search for "ante Christum" in a 1748 reprint of a 1633 abridgement entitled ''Rationarium temporum'' by Denis Petau
|access-date=1 June 2010
|last=Petau |first = Denis
|year=1758
}}</ref>

===New year===
{{See|New Year}}

When the reckoning from Jesus' incarnation began replacing the previous dating systems in western Europe, various people chose different Christian feast days to begin the year: Christmas, [[Annunciation]], or Easter. Thus, depending on the time and place, the year number changed on different days in the year, which created slightly different styles in chronology:<ref>[[C. R. Cheney]], [http://catdir.loc.gov/catdir/samples/cam032/99027383.pdf ''A Handbook of Dates, for students of British history''] {{Webarchive|url=https://web.archive.org/web/20151205104025/http://catdir.loc.gov/catdir/samples/cam032/99027383.pdf |date=5 December 2015 }}, Cambridge University Press, 1945–2000, pp. 8–14.</ref>
* From 25 March 753 [[Ab urbe condita|AUC]] (today in 1 BC), i.e., notionally from the incarnation of Jesus. That first "Annunciation style" appeared in [[Arles]] at the end of the 9th century then spread to Burgundy and northern Italy. It was not commonly used and was called ''calculus pisanus'' since it was adopted in [[Pisa]] and survived there until 1750.
* From 25 December 753 AUC (today in 1 BC), i.e., notionally from the birth of Jesus. It was called "Nativity style" and had been spread by Bede together with the ''Anno Domini'' in the early Middle Ages. That reckoning of the Year of Grace from Christmas was used in France, England and most of western Europe (except Spain) until the 12th century (when it was replaced by Annunciation style) and in Germany until the second quarter of the 13th century.
* From 25 March 754 AUC (today in AD 1). That second "Annunciation style" may have originated in [[Fleury Abbey]] in the early 11th century, but it was spread by the Cistercians. [[Florence]] adopted that style in opposition to that of Pisa, so it got the name of ''calculus florentinus''. It soon spread in France and also in England where it became common in the late 12th century and lasted until 1752.
* From Easter, starting in 754 AUC (AD 1). That ''mos gallicanus'' (French custom) bound to a [[moveable feast]] was introduced in France by king [[Philip II of France|Philip Augustus]] (r. 1180–1223), maybe to establish a new style in the provinces reconquered from England. However, it never spread beyond the ruling élite.
With these various styles, the same day could, in some cases, be dated in 1099, 1100 or 1101.

==Other Christian and European eras==
{{further|Calendar era}}
During the first six centuries of what would come to be known as the Christian era, European countries used various systems to count years. Systems in use included [[List of Roman consuls|consular dating]], imperial [[regnal year]] dating, and [[Anno Mundi|Creation dating]].

Although the last non-imperial consul, [[Anicius Faustus Albinus Basilius|Basilius]], was appointed in 541 by Emperor [[Justinian I]], later emperors through to [[Constans II]] (641–668) were appointed consuls on the first of January after their accession. All of these emperors, except Justinian, used imperial post-consular years for the years of their reign, along with their regnal years.<ref>Roger S. Bagnall and [[Klaas Worp|Klaas A. Worp]], ''[https://openaccess.leidenuniv.nl/handle/1887/11125 Chronological Systems of Byzantine Egypt] {{Webarchive|url=https://web.archive.org/web/20110717092648/https://openaccess.leidenuniv.nl/handle/1887/11125 |date=17 July 2011 }}'', Leiden, Brill, 2004.{{page needed|date=November 2023}}</ref> Long unused, this practice was not formally abolished until Novell XCIV of the law code of [[Leo VI the Wise|Leo VI]] did so in 888.

Another calculation had been developed by the [[Alexandria]]n monk [[Annianus of Alexandria|Annianus]] around the year AD 400, placing the Annunciation on 25 March AD 9 (Julian)—eight to ten years after the date that Dionysius was to imply. Although this incarnation was popular during the early centuries of the [[Byzantine Empire]], years numbered from it, an ''Era of Incarnation'', were exclusively used and are still used in [[Ethiopia]]. This accounts for the seven- or eight-year discrepancy between the [[Gregorian calendar|Gregorian]] and [[Ethiopian calendar]]s. 

Byzantine chroniclers like [[Maximus the Confessor]], [[George Syncellus]], and [[Theophanes the Confessor|Theophanes]] dated their years from Annianus' [[Genesis creation narrative|creation]] of the world. This era, called ''[[Anno Mundi]]'', "year of the world" (abbreviated AM), by modern scholars, began its first year on 25 March 5492 BC. Later Byzantine chroniclers used ''Anno Mundi'' years from 1 September 5509 BC, the [[Byzantine calendar|Byzantine Era]]. No single ''Anno Mundi'' epoch was dominant throughout the [[Christian world]]. [[Eusebius of Caesarea]] in his ''[[Chronicon (Eusebius)|Chronicle]]'' used an era beginning with the birth of [[Abraham]], dated in 2016 BC (AD 1 = 2017 Anno Abrahami).<ref>Alfred von Gutschmid, ''Kleine Schriften'', F. Ruehl, Leipzig, 1889, p.&nbsp;433.</ref>

Spain and Portugal continued to date by the [[Spanish Era]] (also called [[Era of the Caesars]]), which began counting from 38 BC, well into the Middle Ages. In 1422, [[Portugal]] became the last Catholic country to adopt the ''Anno Domini'' system.<ref name=CathEncy/>

The [[Era of Martyrs]], which numbered years from the accession of [[Diocletian]] in 284, who launched the most severe [[persecution of Christians]], was used by the [[Coptic Orthodox Church|Church of Alexandria]] and is still used, officially, by the Coptic Orthodox and [[Coptic Catholic Church|Coptic Catholic]] churches. It was also used by the [[Ethiopian Orthodox Tewahedo Church|Ethiopian]] and [[Eritrean Orthodox Tewahedo Church|Eritrean]] churches. Another system was to date from the [[crucifixion of Jesus]], which as early as [[Hippolytus (writer)|Hippolytus]] and [[Tertullian]] was believed to have occurred in the consulate of the Gemini (AD 29), which appears in some [[Middle Ages|medieval]] manuscripts.

== CE and BCE ==
{{Main|Common Era}}

Alternative names for the ''Anno Domini'' era include ''vulgaris aerae'' (found 1615 in Latin),<ref name="VulgarisAerae1">
{{cite book
|quote=anno aerae nostrae vulgaris
|author=Johannes Kepler
|title=Joannis Keppleri Eclogae chronicae: ex epistolis doctissimorum aliquot virorum & suis mutuis, quibus examinantur tempora nobilissima: 1. Herodis Herodiadumque, 2. baptismi & ministerii Christi annorum non plus 2 1/4, 3. passionis, mortis et resurrectionis Dn. N. Iesu Christi, anno aerae nostrae vulgaris 31. non, ut vulgo 33., 4. belli Iudaici, quo funerata fuit cum Ierosolymis & Templo Synagoga Iudaica, sublatumque Vetus Testamentum. Inter alia & commentarius in locum Epiphanii obscurissimum de cyclo veteri Iudaeorum.
|publisher=Francofurti : Tampach
|language = la
|year=1615
|oclc = 62188677|author-link = Johannes Kepler}}</ref>
"Vulgar Era" (in English, as early as 1635),<ref name=1635VulgarinEnglish>
{{cite book |url=https://books.google.com/books?id=prP9cQAACAAJ&q=vulgar+era
|author1=Kepler, Johann
|author2=Vlacq, Adriaan
|year=1635
|title=Ephemerides of the Celestiall Motions, for the Yeers of the Vulgar Era 1633...
|access-date=18 May 2011
}}</ref>{{efn|The word ''[[wikt:vulgar|vulgar]]'' originally meant "of the ordinary people", distinguishing it from the [[regnal date]] (years since the coronation of the monarch).}}
"Christian Era" (in English, in 1652),<ref>
{{cite book |url = http://www.google.com/products?q=Ephemeris+year+Christian+era+1652 |title=A celestiall glasse, or, Ephemeris for the year of the Christian era 1652 being the bissextile or leap-year: contayning the lunations, planetary motions, configurations & ecclipses for this present year ... : with many other things very delightfull and necessary for most sorts of men: calculated exactly and composed for ... Rochester
|last = Sliter |first = Robert
|year=1652
|publisher=Printed for the Company of Stationers
|location=London
}}</ref>
"[[Common Era]]" (in English, 1708),<ref name=1708CommonInEnglish>
{{cite book |url = https://books.google.com/books?id=D_wvAAAAYAAJ&q=%22common+era%22 |publisher=Printed for H. Rhodes |title=The History of the Works of the Learned |volume=10 |page=513 |location=London |year=1708 |access-date = 18 May 2011 }}</ref>
and "Current Era".<ref name=CurrentEra>
{{cite web |url = http://www.bbc.co.uk/religion/religions/judaism/history/history_1.shtml#section_2 |title=History of Judaism 63BCE–1086CE |quote=Year 1: CE – What is nowadays called the 'Current Era' traditionally begins with the birth of a Jewish teacher called Jesus. His followers came to believe he was the promised Messiah and later split away from Judaism to found Christianity |date=8 February 2005 |work=BBC Team |publisher=BBC |access-date=18 May 2011 |archive-url = https://web.archive.org/web/20110513215113/http://www.bbc.co.uk/religion/religions/judaism/history/history_1.shtml |archive-date=13 May 2011 |url-status= live }}
</ref>
Since 1856,<ref>
{{cite book
 |url = https://archive.org/details/postbiblicalhis05raphgoog
 |quote = CE BCE.
 |title=Post-Biblical History of The Jews
 |publisher=Moss & Brother
 |last = Raphall |first = Morris Jacob
 |year=1856
 |access-date=18 May 2011
}}
The term ''common era'' does not appear in this book; the term ''Christian era'' [lowercase] does appear a number of times. Nowhere in the book is the abbreviation explained or expanded directly.
</ref> the alternative abbreviations [[Common Era|CE and BCE]] (sometimes written C.E. and B.C.E.) are sometimes used in place of AD and BC.

The "Common/Current Era" ("CE") terminology is often preferred by those who desire a term that does not explicitly make religious references but still uses the same epoch as the Anno Domini notation.<ref>{{cite web |url = http://www.religioustolerance.org/ce_info1.htm |last=Robinson |first = B.A.|title=Justification of the use of "CE" & "BCE" to identify dates. Trends |website = ReligiousTolerance.org |date=20 April 2009 |url-status=dead |archive-url=https://web.archive.org/web/20110511090102/http://www.religioustolerance.org/ce_info1.htm |archive-date=11 May 2011}}</ref><ref>{{cite magazine |url = https://www.nytimes.com/1997/08/17/magazine/bc-ad-or-bce-ce.html |first = William |last = Safire |title = On Language: B.C./A.D. or B.C.E./C.E.? |magazine=[[The New York Times Magazine]] |date=17 August 1997 |archive-url=https://web.archive.org/web/20130612195845/https://www.nytimes.com/1997/08/17/magazine/bc-ad-or-bce-ce.html |archive-date=12 June 2013}}</ref>
For example, Cunningham and Starr (1998) write that "B.C.E./C.E. […] do not presuppose faith in [[Jesus Christ|Christ]] and hence are more appropriate for [[interfaith dialog]] than the conventional B.C./A.D."<ref name=Cunningham2004>{{cite book |editor-last=Cunningham |editor-first = Philip A. |title=Pondering the Passion : what's at stake for Christians and Jews? |year=2004 |publisher=[[Rowman & Littlefield]] |location=Lanham, Md. [u.a.] |isbn=978-0742532182 |page=193 |url=https://books.google.com/books?id=IN5VAAAAYAAJ&q=%22not+presuppose+faith+in+Christ%22 }}</ref> Upon its foundation, the [[Republic of China (1912–1949)|Republic of China]] adopted the [[Minguo Era]] but used the Western calendar for international purposes. The translated term was {{linktext|lang=zh|西|元}} ({{zh|labels=no|p=xī yuán |l=Western Era}}). Later, in 1949, the People's Republic of China adopted {{linktext|lang=zh|公元}} ({{zh|labels=no|p=gōngyuán |l=Common Era}}) for all purposes domestic and foreign.

== No year zero: start and end of a century ==
{{Further|Year zero|Astronomical year numbering|Millennium|Century|Decade}}

In the AD year numbering system, whether applied to the [[Julian calendar|Julian]] or [[Gregorian calendar]]s, AD 1 is immediately preceded by 1 BC, with nothing in between them (there was no [[year zero]]). There are debates as to whether a new decade, century, or millennium begins on a year ending in zero or one.<ref name="Teresi1997" />

For computational reasons, [[astronomical year numbering]] and the [[ISO 8601]] standard designate years so that AD 1 = year 1, 1 BC = year 0, 2 BC = year −1, etc.{{efn|To convert from a year BC to [[astronomical year numbering]], reduce the absolute value of the year by 1, and prefix it with a negative sign (unless the result is zero). For years AD, omit the AD and prefix the number with a plus sign (plus sign is optional if it is clear from the context that the year is after the year 0).<ref>Doggett, 1992, p. 579</ref>}} In common usage, ancient dates are expressed in the Julian calendar, but ISO 8601 uses the Gregorian calendar and astronomers may use a variety of time scales depending on the application. Thus dates using the year 0 or negative years may require further investigation before being converted to BC or AD.

== See also ==
* [[Before Present]]
* [[Holocene calendar]]

== Notes ==
{{notelist}}

== References ==
=== Citations ===
{{Reflist}}

=== Sources ===
{{refbegin}}
* {{cite book
 | title = Oxford Pocket Dictionary and Thesaurus
 | editor-last = Abate
 | editor-first = Frank R.
 | version = American
 | location = New York
 | publisher = Oxford University Press
 | year = 1997
 | isbn = 0-19-513097-9
 }}
* {{cite book
 |title = Associated Press Style Book
 |publisher = Basic Books
 |location = New York
 |editor1-first = Norm
 |editor1-last = Goldstein
 |year = 2007
 |isbn = 978-0-465-00489-8
 }}
* Bede. (731). [http://www.thelatinlibrary.com/bede/bede1.shtml ''Historiam ecclesiasticam gentis Anglorum''] {{Webarchive|url=https://web.archive.org/web/20201109215631/http://www.thelatinlibrary.com/bede/bede1.shtml |date=9 November 2020 }}. Retrieved 2007-12-07.
* {{cite book | year = 1993 | title = Chicago Manual of Style | edition = 2nd | publisher = University of Chicago | isbn = 0-226-10389-7 | url = https://archive.org/details/chicagomanualofs00chic }}
* {{cite book | year = 2010 | title = Chicago Manual of Style | edition = 16th | publisher = University of Chicago | isbn = 978-0-226-10420-1}}
* {{cite book
| last1 = Blackburn
| first1 = Bonnie
| author1-link = Bonnie J. Blackburn
| first2 = Leofranc
| last2 = Holford-Strevens
| author2-link = Leofranc Holford-Strevens
| title = The Oxford Companion to the Year: an exploration of calendar customs and time-reckoning
| publisher = Oxford University Press
| location = Oxford
| year = 2003
| isbn = 0-19-214231-3
| url = https://archive.org/details/oxfordcompaniont00blac
}} Corrected reprinting of original 1999 edition.
* {{cite book
 | author = Cunningham, Philip A.
 | author2 = Starr, Arthur F.
 | year = 1998
 | title = Sharing Shalom: A Process for Local Interfaith Dialogue Between Christians and Jews
 | publisher = Paulist Press
 | isbn = 0-8091-3835-2
}}
* {{cite book
 | last = Declercq | first = Georges
 | title = Anno Domini: the origins of the Christian era
 | location = Turnhout
 | publisher = Brepols
 | year = 2000
 | isbn = 2-503-51050-7
 }} (despite beginning with 2, it is English)
* Declercq, G. "Dionysius Exiguus and the Introduction of the Christian Era". ''Sacris Erudiri'' 41 (2002): 165–246. An annotated version of part of ''Anno Domini''.
* Doggett. (1992). [http://eclipse.gsfc.nasa.gov/SEhelp/calendars.html "Calendars"] {{Webarchive|url=https://web.archive.org/web/20191208132404/https://eclipse.gsfc.nasa.gov/SEhelp/calendars.html |date=8 December 2019 }} (Ch. 12), in P. Kenneth Seidelmann (Ed.) ''Explanatory supplement to the astronomical almanac.'' Sausalito, CA: University Science Books. {{ISBN|0-935702-68-7}}.
* Patrick, J. (1908). [http://www.newadvent.org/cathen/03738a.htm "General Chronology"] {{Webarchive|url=https://web.archive.org/web/20210125003503/https://www.newadvent.org/cathen/03738a.htm |date=25 January 2021 }}. In ''The Catholic Encyclopedia''. New York: Robert Appleton Company. Retrieved 2008-07-16 from New Advent: [http://www.newadvent.org/cathen/03738a.htm Catholic Encyclopedia: General Chronology] {{Webarchive|url=https://web.archive.org/web/20210125003503/https://www.newadvent.org/cathen/03738a.htm |date=25 January 2021 }}
* {{cite book
 | last = Richards
 | first = E. G.
 | title = Mapping Time
 | url = https://archive.org/details/mappingtimecalen00rich
 | url-access = registration
 | location = Oxford
 | publisher = Oxford University Press
 | year = 2000
 | isbn = 0-19-286205-7
 }}
* {{cite web
 | last = Riggs
 | first = John
 | date = January 2003
 | url = http://www.ucc.org/ucnews/janfeb03/whatever-happened-to-bc-and.html
 | title = Whatever happened to B.C. and A.D., and why?
 | publisher = United Church News
 | access-date = 19 December 2005
 | archive-date = 28 February 2014
 | archive-url = https://web.archive.org/web/20140228195410/http://www.ucc.org/ucnews/janfeb03/whatever-happened-to-bc-and.html
 | url-status = dead
 }}
* {{cite book
|last=Ryan
|first=Donald P.
|year=2000
|title=The Complete Idiot's Guide to Biblical Mysteries
|publisher=Alpha Books
|url=https://archive.org/details/completeidiotsgu00ryan
|url-access=registration
|quote=must mean after death not so.
|page=[https://archive.org/details/completeidiotsgu00ryan/page/15 15]
|isbn=0-02-863831-X
}}
{{refend}}

== External links ==
{{Wiktionary|AD|Anno Domini}}
* [http://www.fourmilab.ch/documents/calendar/ Calendar Converter]

{{-}}

{{Calendars}}
{{Chronology}}

{{Interwiki conflict}}

[[Category:6th-century Christianity]]
[[Category:Calendar eras]]
[[Category:Christian terminology]]
[[Category:Chronology]]
[[Category:Latin religious words and phrases]]
[[Category:Timelines of Christianity]]