The termsanno Domini (AD) andbefore Christ (BC) are used when designating years in theGregorian andJulian calendars. The termanno Domini isMedieval Latin and means "in the year of the Lord"[1] but is often presented using "our Lord" instead of "the Lord",[2][3] taken from the full original phrase "anno Domini nostri Jesu Christi", which translates to "in the year of our LordJesus Christ". The form "BC" is specific toEnglish, and equivalent abbreviations are used in other languages: theLatin form, rarely used in English, isante Christum natum (ACN) orante Christum (AC).
Thiscalendar era takes as itsepoch the traditionally reckoned year of theconception orbirth of Jesus. YearsAD are counted forward since that epoch and yearsBC are counted backward from the epoch. There is noyear zero in this scheme; thus the yearAD 1 immediately follows the year1 BC. This dating system was devised in 525 byDionysius Exiguus but was not widely used until the 9th century.[4][5] (Modern scholars believe that the actualdate of birth of Jesus was about 5 BC.[6][7][8][9])
Terminology that is viewed by some as being more neutral and inclusive of non-Christian people is to call this theCommon Era (abbreviated as CE), with the preceding years referred to as Before the Common Era (BCE).Astronomical year numbering andISO 8601 do not use words or abbreviations related to Christianity, but use the same numbers for AD years (but not for BC years since the astronomical year 0 is 1 BC).
Traditionally, English follows Latin usage by placing the "AD" abbreviation before the year number, though it is also found after the year.[10] In contrast, "BC" is always placed after the year number (for example: 70 BC but AD 70), which preserves syntactic order. The abbreviation "AD" is also widely used after the number of a century ormillennium, as in "fourth century AD" or "second millennium AD" (although conservative usage formerly rejected such expressions).[11] Since "BC" is the English abbreviation forBefore Christ, it is sometimes incorrectly concluded that AD meansAfter Death (i.e., after thedeath of Jesus), which would mean that the approximately 33 years commonly associated with thelife of Jesus would be included in neither the BC nor the AD time scales.[12]
Theanno Domini dating system was devised in 525 byDionysius Exiguus to enumerate years inhis Easter table. His system was to replace theDiocletian era that had been used inolder Easter tables, as he did not wish to continue the memory of a tyrant whopersecuted Christians.[13] The last year of the old table, DiocletianAnno 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 theconsuls who held office that year— Dionysius himself stated that the "present year" was "the consulship ofProbus Junior", which was 525 years "since the incarnation of our Lord Jesus Christ".[14] Thus, Dionysius implied thatJesus' 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,year of the world, orregnal year of Augustus; much less does he explain or justify the underlying date."[15]
In modern times,incarnation is synonymous with the conception, but some ancient writers, such asBede, 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 theGospel 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.[16][17][18] This method was probably the one used by ancient historians such asTertullian,Eusebius orEpiphanius, all of whom agree that Jesus was born in 2 BC,[19] probably following this statement of Jesus' age (i.e. subtracting thirty years from AD 29).[20] Alternatively, Dionysius may have used an earlier unknown source. TheChronograph of 354 states that Jesus was born during the consulship ofCaesar andPaullus (AD 1), but the logic behind this is also unknown.[21]
It has also been speculated by Georges Declercq[22] that Dionysius' desire to replace Diocletian years with a calendar based on the incarnation of Christ was intended to prevent people from believing the imminentend of the world. At the time, it was believed by some that theresurrection of the dead and end of the world would occur 500 years after the birth of Jesus. The oldAnno Mundi calendar theoretically commenced with thecreation of the world based on information in theOld Testament. It was believed that, based on theAnno Mundi calendar, Jesus was born in the year 5500 (5500 years after the world was created) with the year 6000 of theAnno Mundi calendar marking the end of the world.[23][18]Anno Mundi 6000 (approximately AD 500) was thus equated with the end of the world[22] 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.[24]
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.[25] The historical evidence is too fragmentary to allow a definitive dating,[26] 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 theministry of Jesus.[27][28]
TheAnglo-Saxon historianBede, who was familiar with the work of Dionysius Exiguus, usedanno Domini dating in hisEcclesiastical History of the English People, which he completed in AD 731. In theHistory he also used theLatin phraseante [...] 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.[29] Both Dionysius and Bede regardedanno Domini as beginning at the incarnation ofJesus 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., theAnnunciation on March 25" ("Annunciation style" dating).[30]
On the continent of Europe,anno Domini was introduced as the era of choice of theCarolingian Renaissance by the English cleric and scholarAlcuin in the late eighth century. Its endorsement by EmperorCharlemagne andhis successors popularizing the use of the epoch and spreading it throughout theCarolingian Empire ultimately lies at the core of the system's prevalence. According to theCatholic Encyclopedia, popes continued to date documents according toregnal years for some time, but usage of AD gradually became more common in Catholic countries from the 11th to the 14th centuries.[31] In 1422,Portugal became the last Western European country toswitch to the system begun by Dionysius.[32]Eastern Orthodox countries only began to adopt AD instead of theByzantine calendar in 1700 when Russia did so, with others adopting it in the 19th and 20th centuries.
Althoughanno 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.[a] In 1627, the FrenchJesuit theologianDenis Pétau (Dionysius Petavius in Latin), with his workDe doctrina temporum, popularized the usageante Christum (Latin for "Before Christ") to mark years prior to AD.[33][34][35]
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:[36]
From 25 March 753AUC (1 BC), i.e., notionally from the incarnation of Jesus. That first "Annunciation style" appeared inArles at the end of the 9th century then spread to Burgundy and northern Italy. It was not commonly used and was calledcalculus pisanus since it was adopted inPisa and survived there until 1750.
From 25 December 753 AUC (1 BC), i.e., notionally from the birth of Jesus. It was called "Nativity style" and had been spread by Bede together with theanno 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 (AD 1). That second "Annunciation style" may have originated inFleury 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 ofcalculus 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. Thatmos gallicanus (French custom) bound to amoveable feast was introduced in France by kingPhilip 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.
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 includedconsular dating, imperialregnal year dating, andCreation dating.
Although the last non-imperial consul,Basilius, was appointed in 541 by EmperorJustinian I, later emperors through toConstans 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.[37] Long unused, this practice was not formally abolished until Novell XCIV of the law code ofLeo VI did so in 888.
Another calculation had been developed by theAlexandrian monkAnnianus 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 theByzantine Empire, years numbered from it, anEra of Incarnation, were exclusively used and are still used inEthiopia. This accounts for the seven- or eight-year discrepancy between theGregorian andEthiopian calendars.
Byzantine chroniclers likeMaximus the Confessor,George Syncellus, andTheophanes dated their years from Annianus'creation of the world. This era, calledAnno Mundi, "year of the world" (abbreviated AM), by modern scholars, began its first year on 25 March 5492 BC. Later Byzantine chroniclers usedAnno Mundi years from 1 September 5509 BC, theByzantine Era. No singleAnno Mundi epoch was dominant throughout theChristian world.Eusebius of Caesarea in hisChronicle used an era beginning with the birth ofAbraham, dated in 2016 BC (AD 1 = 2017 Anno Abrahami).[38]
Spain and Portugal continued to date by theSpanish Era (also calledEra of the Caesars), which began counting from 38 BC, well into the Middle Ages. In 1422,Portugal became the last Catholic country to adopt theanno Domini system.[31]
Alternative names for theanno Domini era includevulgaris aerae (found 1615 in Latin),[39]"Vulgar Era" (in English, as early as 1635),[40][b]"Christian Era" (in English, in 1652),[41]"Common Era" (in English, 1708),[42]and "Current Era".[43]Since 1856,[44] the alternative abbreviationsCE 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 theanno Domini notation.[45][46]For example, Cunningham and Starr (1998) write that "B.C.E./C.E. […] do not presuppose faith inChrist and hence are more appropriate forinterfaith dialog than the conventional B.C./A.D."[47] Upon its foundation, theRepublic of China adopted theMinguo Era but used the Western calendar for international purposes. The translated term was西元 (xī yuán; 'Western Era'). Later, in 1949, the People's Republic of China adopted公元 (gōngyuán; 'Common Era') for all purposes domestic and foreign.
In the AD year numbering system, whether applied to theJulian orGregorian calendars, AD 1 is immediately preceded by 1 BC, with nothing in between them (there was noyear zero). There are debates as to whether a new decade, century, or millennium begins on a year ending in zero or one.[4]
For computational reasons,astronomical year numbering and theISO 8601 standard designate years so that AD 1 = year 1, 1 BC = year 0, 2 BC = year −1, etc.[c] 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.
^Werner Rolevinck inFasciculus temporum (1474) usedAnno ante xpi nativitatem (in the year before the birth of Christ) for all years betweencreation and Jesus. "xpi" comes from theGreek χρ (chr) in visually Latin letters, together with the Latin ending -i, thus abbreviatingChristi ("of Christ"). This phrase appears upside down in the centre ofrecto folios (right hand pages). From Jesus toPope Sixtus IV he usually usedAnno Christi or its abbreviated formAnno xpi (onverso folios—left hand pages). He usedAnno mundi alongside all of these terms for all years.
^The wordvulgar originally meant "of the ordinary people", distinguishing it from theregnal date (years since the coronation of the monarch).
^To convert from a year BC toastronomical 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).[48]
^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".
^Paul L. Maier "The Date of the Nativity and Chronology of Jesus" inChronos, kairos, Christos: nativity and chronological studies by Jerry Vardaman, Edwin M. Yamauchi 1989ISBN0-931464-50-1 pp. 113–29
^New Testament History by Richard L. Niswonger 1992ISBN0-310-31201-9 pp. 121–24
^Alfred von Gutschmid,Kleine Schriften, F. Ruehl, Leipzig, 1889, p. 433.
^Johannes Kepler (1615).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 (in Latin). Francofurti : Tampach.OCLC62188677.anno aerae nostrae vulgaris
^"History of Judaism 63BCE–1086CE".BBC Team. BBC. 8 February 2005.Archived from the original on 13 May 2011. Retrieved18 May 2011.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
^Raphall, Morris Jacob (1856).Post-Biblical History of The Jews. Moss & Brother. Retrieved18 May 2011.CE BCE.The termcommon era does not appear in this book; the termChristian era [lowercase] does appear a number of times. Nowhere in the book is the abbreviation explained or expanded directly.
Cunningham, Philip A.; Starr, Arthur F. (1998).Sharing Shalom: A Process for Local Interfaith Dialogue Between Christians and Jews. Paulist Press.ISBN0-8091-3835-2.
Declercq, Georges (2000).Anno Domini: the origins of the Christian era. Turnhout: Brepols.ISBN2-503-51050-7. (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 ofAnno Domini.
Doggett. (1992)."Calendars"Archived 8 December 2019 at theWayback Machine (Ch. 12), in P. Kenneth Seidelmann (Ed.)Explanatory supplement to the astronomical almanac. Sausalito, CA: University Science Books.ISBN0-935702-68-7.
