The terms anno Domini[(AD or A.D.) and before Christ (BC or B.C.) are used to label or number years in the Julian and Gregorian calendars. The term anno Domini is Medieval Latin, which means in the year of the Lord but is often translated as in the year of our Lord.:782 It is occasionally set out more fully as anno Domini nostri Iesu (or Jesu) Christi ("in the year of Our Lord Jesus Christ").
This calendar era is based on the traditionally reckoned year of the conception or birth of Jesus of Nazareth, withAD counting years from the start of this epoch, and BC denoting years before the start of the era. There is no year zero in this scheme, so the year AD 1 immediately follows the year 1 BC. This dating system was devised in 525, but was not widely used until after 800.
The Gregorian calendar is the most widely used calendar in the world today. For decades, it has been the unofficial global standard, adopted in the pragmatic interests of international communication, transportation, and commercial integration, and recognized by international institutions such as the United Nations and the Universal Postal Union.[self-published source]
Traditionally, English followed Latin usage by placing the "AD" abbreviation before the year number. But BC is placed after the year number (for example: AD 2015, but 68 BC), which also preserves syntactic order. The abbreviation 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). Because 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. However, this would mean that the ~33 years commonly associated with the life of Jesus would not be included in either BC or AD time scales.
Terminology that is viewed by some as being more neutral and inclusive of non-Christian people is to call this the Current, or Common Era (abbreviated as CE or C.E.), with the preceding years referred to as Before the Common, Christian, or Current Era (BCE or B.C.E.). Astronomical year numbering and ISO 8601 avoid words or abbreviations related to Christianity, but use the same numbers for years AD.
The Anno Domini dating system was devised in 525 by Dionysius Exiguus to enumerate the years in his Easter table. His system was to replace the Diocletian era that had been used in an old Easter table because he did not wish to continue the memory of a tyrant who persecuted Christians. The last year of the old table, Diocletian 247, was immediately followed by the first year of his table, AD 532. When he devised his table, Julian calendaryears were identified by naming the consuls who held office that year—he himself stated that the "present year" was "the consulship of Probus Junior", which was 525 years "since the incarnation of our Lord Jesus Christ".Thus Dionysius implied that 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, year of the world, or regnal year of Augustus; much less does he explain or justify the underlying date.":778
Blackburn & Holford-Strevens briefly present arguments for 2 BC, 1 BC, or AD 1 as the year Dionysius intended for the Nativity or Incarnation. Among the sources of confusion are::778–9
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
There were inaccuracies in the list of consuls
There were confused summations of emperors' regnal years
Two major theories are 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 (the period during which the dates of Alexandrian Easter repeat) from the first year of his new table.
It has also been speculated by Georges Declercq that Dionysius' desire to replace Diocletian years with a calendar based on the incarnation of Christ was to prevent people from believing the imminent end of the world. At the time, it was believed by some that the Resurrection and end of the world would occur 500 years after the birth of Jesus. The old Anno Mundi calendar theoretically commenced with the 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 (or 5500 years after the world was created) with the year 6000 of the Anno Mundi calendar marking the end of the world. Anno Mundi 6000 (approximately AD 500) was thus equated with the resurrection and the end of the world but this date had already passed in the time of Dionysius.
The Anglo-Saxon historian the Venerable Bede, who was familiar with the work of Dionysius Exiguus, used Anno Domini dating in his Ecclesiastical History of the English People, completed in 731. In this same history, he also used another Latin term, ante vero incarnationis dominicae tempus anno sexagesimo ("in fact in the 60th year before the time of the Lord's incarnation"), equivalent to the English "before Christ", to identify years before the first year of this era, thus establishing the standard of not using a year zero, even though he used zero in his computus. Both Dionysius and Bede regarded Anno Domini as beginning at the incarnation of Jesus, 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).:881
Even though Anno Domini was in widespread use by the 9th century, Before Christ (or its equivalent) did not become common until much later. Bede used the expression "anno igitur ante incarnationem Dominicam" (so in the year before the Incarnation of the Lord) twice. "Anno an xpi nativitate" (in the year before the birth of Christ) is found in 1474 in a work by a German monk. In 1627, the French JesuittheologianDenis 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.
When the reckoning from Jesus' incarnation started replacing the previous dating systems in western Europe, different 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:
From 25 March 753 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 till 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 the Venerable Bedetogether 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 Augustus (1165–1180–1223), 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.
The Gospel of Luke states that Jesus was conceived during the reign of Herod the Great[Luke 1:5-38] (i.e., before 4 BC) while also stating that Jesus was born when Cyrenius(or Quirinius) was the governor of Syria and carried out the census of the Roman provinces of Syria and Iudaea.[Luke 2:1-3] The Jewish historian Josephus, in his Antiquities of the Jews (ca. AD 93), indicates that Cyrenius/Quirinius' governorship of Syria began in AD 6, and that the census occurred sometime between AD 6–7, which is incompatible with a conception prior to 4 BC. On this point, Blackburn and Holford-Strevens state that "St. Luke raises greater difficulty ... Most critics therefore discard Luke".
The Gospel of Luke also states that Jesus was "about thirty years old" [Luke 3:23] during the 15th year of the reign of Tiberius Caesar [Luke 3:1]. Tiberius began his reign as Caesar in September of AD 14. The 15th year of his reign would then be AD 28 or 29. If Jesus was born in 5 or 4 BC, that would put the start of Jesus' ministry around age 32 to 34. Most scholars do not see this as a contradiction of Luke's claim that Jesus was "about thirty years old". Some scholars rely on John 8:57: "thou art not yet fifty years old", making the earliest possible year for Jesus's birth c. 18 BC.:776
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, imperial regnal year dating, and Creation dating.
Although the last non-imperial consul, Basilius, was appointed in 541 by Emperor Justinian I, later emperors through Constans II (641–668) were appointed consuls on the first 1 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. Long unused, this practice was not formally abolished until Novell XCIV of the law code of Leo VI did so in 888.
Another calculation had been developed by the Alexandrian monk 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 yet used, in Ethiopia. This accounts for the seven- or eight-year discrepancy between the Gregorian and Ethiopian calendars. Byzantine chroniclers like Maximus the Confessor, George Syncellus, and Theophanes dated their years from Annianus' 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 Mundiyears from 1 September 5509 BC, the Byzantine Era. No single Anno Mundi epoch was dominant throughout the Christian world. Eusebius of Caesarea in his Chronicleused an era beginning with the birth of Abraham, dated in 2016 BC (AD 1 = 2017 Anno Abrahami).
Spain and Portugal continued to date by the Era of the Caesars or Spanish Era, 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.
Alternative names for the Anno Domini era include vulgaris aerae (found 1615 in Latin), "Vulgar Era" (in English, as early as 1635), "Christian Era" (in English, in 1652), "Common Era" (in English, 1708), and "Current Era". Since 1856, the alternative abbreviations CE and BCE, (sometimes written C.E. and B.C.E.) are sometimes used in place of AD and BC.
The "Common/Christian/Current Era" ("CE") terminology is often preferred by those who desire a term that does not explicitly use religious titles. For example, Cunningham and Starr (1998) write that "B.C.E./C.E. …do not presuppose faith in Christ and hence are more appropriate for interfaith dialog than the conventional B.C./A.D." Upon its foundation, the Republic of China adopted the Minguo 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 the Julian or Gregorian calendars, AD 1 is preceded by 1 BC. There is no year "0" between them. Because of this, most experts agree that a new century begins in a year with the last digits being "01" (1801, 1901, 2001); new millennia likewise began in 1001 and 2001. A common misconception is that centuries and millennia begin when the trailing digits are zeroes (1800, 1900, 2000, etc.); moreover, this convention was widely used to celebrate the new millennium in the year 2000. 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. In common use, 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.