Common Era (CE) and Before the Common Era (BCE) are year notations for the Gregorian calendar (and its predecessor, the Julian 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. [1] [2]
The expression can be traced back to 1615, when it first appears in a book by Johannes Kepler as the Latin : annus aerae nostrae vulgaris (year of our common era), [3] [4] and to 1635 in English as "Vulgar Era". [lower-alpha 1] The term "Common Era" can be found in English as early as 1708, [5] and became more widely used in the mid-19th century by Jewish religious scholars. Since the later 20th century, BCE and CE have become popular in academic and scientific publications because BCE and CE are religiously neutral terms. [6] [7] They are used by others who wish to be sensitive to non-Christians by not explicitly referring to Jesus as "Christ" nor as Dominus ("Lord") through use of the other abbreviations. [8] [9] [lower-alpha 2] [lower-alpha 3]
The idea of numbering years beginning from the date then believed to be the date of birth of Jesus, was conceived around the year 525 by the Christian monk Dionysius Exiguus. He did this to replace the then dominant Era of Martyrs system, because he did not wish to continue the memory of a tyrant who persecuted Christians. [11] He numbered years from an initial reference date ("epoch"), an event he referred to as the Incarnation of Jesus. [11] [12] [13] Dionysius labeled the column of the table in which he introduced the new era as "Anni Domini Nostri Jesu Christi". [14]
This way of numbering years became more widespread in Europe with its use by Bede in England in 731. Bede also introduced the practice of dating years before what he supposed was the year of birth of Jesus, [15] and the practice of not using a year zero. [lower-alpha 4] In 1422, Portugal became the last Western European country to switch to the system begun by Dionysius. [16]
The term "Common Era" is traced back in English to its appearance as "Vulgar Era" to distinguish dates on the Ecclesiastic calendar in popular use from dates of the regnal year, the year of the reign of a sovereign, typically used in national law. (The word 'vulgar' originally meant 'of the ordinary people', with no derogatory associations.)
The first known use of the Latin term anno aerae nostrae vulgaris [lower-alpha 5] occurred in a 1615 book by Johannes Kepler. [4] Kepler uses it again, as ab Anno vulgaris aerae, in a 1616 table of ephemerides, [17] and again, as ab anno vulgaris aerae, in 1617. [18] A 1635 English edition of that book has the title page in English – so far, the earliest-found use of Vulgar Era in English. [19] A 1701 book edited by John LeClerc includes "Before Christ according to the Vulgar Æra, 6". [20] A 1716 book in English by Dean Humphrey Prideaux says, "before the beginning of the vulgar æra, by which we now compute the years from his incarnation." [21] [22] A 1796 book uses the term "vulgar era of the nativity". [23]
The first known use of "Christian Era" appears as the Latin phrase annus aerae christianae on the title page of a 1584 theology book. [24] In 1649, the Latin phrase annus æræ Christianæ appeared in the title of an English almanac. [25] A 1652 ephemeris is the first instance found so far of the English use of "Christian Era". [26]
The English phrase "Common Era" appears at least as early as 1708, [5] and in a 1715 book on astronomy it is used interchangeably with "Christian Era" and "Vulgar Era". [27] A 1759 history book uses common æra in a generic sense, to refer to the common era of the Jews. [28] The first use found so far of the phrase "before the common era" is in a 1770 work that also uses common era and vulgar era as synonyms, in a translation of a book originally written in German. [29] The 1797 edition of the Encyclopædia Britannica uses the terms vulgar era and common era synonymously (meaning not the regnal year). [30] In 1835, in his book Living Oracles , Alexander Campbell, wrote: "The vulgar Era, or Anno Domini; the fourth year of Jesus Christ, the first of which was but eight days", [31] and also refers to the common era as a synonym for vulgar era with "the fact that our Lord was born on the 4th year before the vulgar era, called Anno Domini, thus making (for example) the 42d year from his birth to correspond with the 38th of the common era". [32] The Catholic Encyclopedia (1909) in at least one article reports all three terms (Christian, Vulgar, Common Era) being commonly understood by the early 20th century. [33]
The phrase "common era", in lower case, also appeared in the 19th century in a 'generic' sense, not necessarily to refer to the Christian Era, but to any system of dates in common use throughout a civilization. Thus, "the common era of the Jews", [34] [35] "the common era of the Mahometans", [36] "common era of the world", [37] "the common era of the foundation of Rome". [38] When it did refer to the Christian Era, it was sometimes qualified, e.g., "common era of the Incarnation", [39] "common era of the Nativity", [40] or "common era of the birth of Christ". [41]
An adapted translation of Common Era into Latin as Era Vulgaris (era – or, with a macron, ēra – being an alternative form of aera; aera is the usual form [42] ) was adopted in the 20th century by some followers of Aleister Crowley, and thus the abbreviation "e.v." or "EV" may sometimes be seen as a replacement for AD. [43]
Although Jews have their own Hebrew calendar, they often use the Gregorian calendar without the AD prefix. [44] As early as 1825, the abbreviation VE (for Vulgar Era) was in use among Jews to denote years in the Western calendar. [45] As of 2005 [update] , Common Era notation has also been in use for Hebrew lessons for more than a century. [46] In 1856, Rabbi and historian Morris Jacob Raphall used the abbreviations CE and BCE in his book Post-Biblical History of The Jews. [47] [lower-alpha 6] Jews have also used the term Current Era. [49]
Some academics in the fields of theology, education, archaeology and history have adopted CE and BCE notation despite some disagreement. [50] Several style guides now prefer or mandate its use. [51]
In 2002, an advisory panel for the religious education syllabus for England and Wales recommended introducing BCE/CE dates to schools, [52] and by 2018 some local education authorities were using them. [53] In 2018, the National Trust said it would continue to use BC/AD as its house style. [53] English Heritage explains its era policy thus: "It might seem strange to use a Christian calendar system when referring to British prehistory, but the BC/AD labels are widely used and understood." [54] Some parts of the BBC use BCE/CE, but some presenters have said they will not. [53] As of October 2019, the BBC News style guide has entries for AD and BC, but not for CE or BCE. [55]
The style guide for The Guardian says, under the entry for CE/BCE: "some people prefer CE (common era, current era, or Christian era) and BCE (before common era, etc) to AD and BC, which, however, remain our style". [56]
In the United States, the use of the BCE/CE notation in textbooks was reported in 2005 to be growing. [46] Some publications have transitioned to using it exclusively. For example, the 2007 World Almanac was the first edition to switch to BCE/CE, ending a period of 138 years in which the traditional BC/AD dating notation was used. BCE/CE is used by the College Board in its history tests, [57] and by the Norton Anthology of English Literature. Others have taken a different approach. The US-based History Channel uses BCE/CE notation in articles on non-Christian religious topics such as Jerusalem and Judaism. [58] The 2006 style guide for the Episcopal Diocese Maryland Church News says that BCE and CE should be used. [59]
In June 2006, in the United States, the Kentucky State School Board reversed its decision to use BCE and CE in the state's new Program of Studies, leaving education of students about these concepts a matter of local discretion. [60] [61] [62]
In 2011, media reports suggested that the BC/AD notation in Australian school textbooks would be replaced by BCE/CE notation. [63] The change drew opposition from some politicians and church leaders. Weeks after the story broke, the Australian Curriculum, Assessment and Reporting Authority denied the rumour and stated that the BC/AD notation would remain, with CE and BCE as an optional suggested learning activity. [64]
In 2013, the Canadian Museum of Civilization (now the Canadian Museum of History) in Gatineau (opposite Ottawa), which had previously switched to BCE/CE, decided to change back to BC/AD in material intended for the public while retaining BCE/CE in academic content. [65]
The use of CE in Jewish scholarship was historically motivated by the desire to avoid the implicit "Our Lord" in the abbreviation AD. Although other aspects of dating systems are based in Christian origins, AD is a direct reference to Jesus as Lord. [66] [67] [68]
Proponents of the Common Era notation assert that the use of BCE/CE shows sensitivity to those who use the same year numbering system as the one that originated with and is currently used by Christians, but who are not themselves Christian. [69]
Former United Nations Secretary-General Kofi Annan [70] has argued:
[T]he Christian calendar no longer belongs exclusively to Christians. People of all faiths have taken to using it simply as a matter of convenience. There is so much interaction between people of different faiths and cultures – different civilizations, if you like – that some shared way of reckoning time is a necessity. And so the Christian Era has become the Common Era. [71]
Adena K. Berkowitz, in her application to argue before the United States Supreme Court, opted to use BCE and CE because "Given the multicultural society that we live in, the traditional Jewish designations –B.C.E. and C.E. – cast a wider net of inclusion". [72]
Christian, non-Christian, and non-religious individuals who oppose the usage of Common Era often note the fact that there is no difference in the origin of the two systems. BCE and CE are still based on BC and AD and denote the periods before and after Jesus was born. [73]
Some oppose the Common Era notation for explicitly religious reasons, because the BC/AD notation is based on the presumptive year of the conception or birth of Jesus: some Christians are offended by the removal of the reference to him in the Common Era notation. [74] The Southern Baptist Convention supports retaining the BC/AD abbreviations. [75]
Roman Catholic priest and writer on interfaith issues Raimon Panikkar argued that the BCE/CE usage is the less inclusive option, since in his view they are still using the Christian calendar, forcing it on other nations. [76]
In 1993, the English-language expert Kenneth G. Wilson speculated a slippery slope scenario in his style guide that "if we do end by casting aside the AD/BC convention, almost certainly some will argue that we ought to cast aside as well the conventional numbering system [that is, the method of numbering years] itself, given its Christian basis." [77] The short-lived French Republican Calendar, for example, began with the first year of the French First Republic and rejected the seven-day week (with its connections to the Book of Genesis) for a ten-day week.[ citation needed ]
The abbreviation BCE, just as with BC, always follows the year number. Unlike AD, which still often precedes the year number, CE always follows the year number (if context requires that it be written at all). [78] Thus, the current year is written as 2023 in both notations (or, if further clarity is needed, as 2023 CE, or as AD 2023), and the year that Socrates died is represented as 399 BCE (the same year that is represented by 399 BC in the BC/AD notation). The abbreviations are sometimes written with small capital letters, or with periods (e.g., "B.C.E." or "C.E."). [79] The US-based Society of Biblical Literature style guide for academic texts on religion prefers BCE/CE to BC/AD. [80]
The terms anno Domini (AD) and before Christ (BC) are used to label or number 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 is Ante Christum natum but is rarely seen.
Astronomical year numbering is based on AD/CE year numbering, but follows normal decimal integer numbering more strictly. Thus, it has a year 0; the years before that are designated with negative numbers and the years after that are designated with positive numbers. Astronomers use the Julian calendar for years before 1582, including the year 0, and the Gregorian calendar for years after 1582, as exemplified by Jacques Cassini (1740), Simon Newcomb (1898) and Fred Espenak (2007).
A century is a period of 100 years. Centuries are numbered ordinally in English and many other languages. The word century comes from the Latin centum, meaning one hundred. Century is sometimes abbreviated as c.
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.
A year is the orbital period of a planetary body, for example, the Earth, moving in its orbit around the Sun. Due to the Earth's axial tilt, the course of a year sees the passing of the seasons, marked by change in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the planet, four seasons are generally recognized: spring, summer, autumn and winter. In tropical and subtropical regions, several geographical sectors do not present defined seasons; but in the seasonal tropics, the annual wet and dry seasons are recognized and tracked.
AD 1 or 1 CE was the epoch year for the Anno Domini (AD) Christian calendar era and also the 1st year of the Common Era (CE) and the 1st millennium and of the 1st century of the Christian and the common era. It was a common year starting on Saturday or Sunday, a common year starting on Saturday by the proleptic Julian calendar, and a common year starting on Monday by the proleptic Gregorian calendar. In the Roman Empire, AD 1 was known as the Year of the Consulship of Caesar and Paullus, named after Roman consuls Gaius Caesar and Lucius Aemilius Paullus, and less frequently, as year AUC 754 within the Roman Empire. The denomination "AD 1" for this year has been in consistent use since the mid-medieval period when the Anno Domini (AD) calendar era became the prevalent method in Europe for naming years. It was the beginning of the Christian era/common era. The preceding year is 1 BC; there is no year 0 in this numbering scheme. The Anno Domini dating system was devised in AD 525 by Dionysius Exiguus.
The proleptic Julian calendar is produced by extending the Julian calendar backwards to dates preceding AD 8 when the quadrennial leap year stabilized. The leap years that were actually observed between the implementation of the Julian calendar in 45 BC and AD 8 were erratic.
Dionysius Exiguus was a 6th-century Eastern Roman monk born in Scythia Minor. He was a member of a community of Scythian monks concentrated in Tomis, the major city of Scythia Minor. Dionysius is best known as the inventor of Anno Domini (AD) dating, which is used to number the years of both the Gregorian calendar and the (Christianised) Julian calendar. Almost all churches adopted his computus for the dates of Easter.
The Thai solar calendar was adopted by King Chulalongkorn in 1888 CE as the Siamese version of the Gregorian calendar, replacing the Thai lunar calendar as the legal calendar in Thailand. Years are now counted in the Buddhist Era (B.E.): พุทธศักราช, พ.ศ., which is 543 years ahead of the Gregorian calendar.
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.
The Era of the Martyrs, also known as the Diocletian era, is a method of numbering years used by the Church of Alexandria beginning in the 4th century AD/CE and by the Coptic Orthodox Church of Alexandria from the 5th century to the present. Western Christians were aware of it but did not use it. It was named for the Roman Emperor Diocletian who instigated the last major persecution against Christians in the Empire. Diocletian began his reign on 20 November 284, during the Alexandrian year that began on 1 Thoth, the Egyptian New Year, or 29 August 284, so that date was used as the epoch: year one of the Diocletian era began on that date. This era was used to number the year in Easter tables produced by the Church of Alexandria.
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:
The Seleucid era ("SE") or Anno Graecorum, sometimes denoted "AG," was a system of numbering years in use by the Seleucid Empire and other countries among the ancient Hellenistic civilizations. It is sometimes referred to as "the dominion of the Seleucidæ," or the Year of Alexander. The era dates from Seleucus I Nicator's re-conquest of Babylon in 312/11 BC after his exile in Ptolemaic Egypt, considered by Seleucus and his court to mark the founding of the Seleucid Empire. According to Jewish tradition, it was during the sixth year of Alexander the Great's reign that they began to make use of this counting. The introduction of the new era is mentioned in one of the Babylonian Chronicles, the Chronicle of the Diadochi.
The Shaka era is a historical Hindu calendar era, the epoch of which corresponds to Julian year 78.
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.
A year zero does not exist in the Anno Domini (AD) calendar year system commonly used to number years in the Gregorian calendar ; in this system, the year 1 BC is followed directly by year AD 1. However, there is a year zero in both the astronomical year numbering system, and the ISO 8601:2004 system, the interchange standard for all calendar numbering systems. There is also a year zero in most Buddhist and Hindu calendars.
The Spanish era, sometimes called the era of Caesar, was a calendar era commonly used in the states of the Iberian Peninsula from the 5th century until the 15th, when it was phased out in favour of the Anno Domini (AD) system. The epoch of the Spanish era was 1 January 38 BC. To convert an Anno Domini date to the corresponding year in the Spanish era, add 38 to the Anno Domini year, such that Era 941 would be equivalent to AD 903. A date given in the Spanish era always uses the word era followed by a feminine ordinal number. This contrasts with the AD system that uses the masculine anno (year): i.e., era millesima octava versus anno millesimo octavo.
The Byzantine calendar, also called the Roman calendar, the Creation Era of Constantinople or the Era of the World, was the calendar used by the Eastern Orthodox Church from c. 691 to 1728 in the Ecumenical Patriarchate. It was also the official calendar of the Byzantine Empire from 988 to 1453 and of Kievan Rus' and Russia from c. 988 to 1700. This calendar was used also in other areas of the Byzantine commonwealth such as in Serbia, where it is found in old Serbian legal documents such as Dušan's Code, thus being referred to as the Serbian Calendar as well. Since Byzantine is a historiographical term, the original name uses the adjective "Roman" as it was what the Eastern Roman Empire continued calling itself.
The Sardica paschal table or Sardica document is a document from a Latin manuscript of the 7th/8th century AD. It is a copy in Latin translation of the creed of the Eastern Christian bishops attending the Council of Sardica who, fearing that their deliberations would be dominated by Western bishops, met separately at Philippopolis. Appended to the creed and anathemas is a table of Paschal full moon dates, given as dates in the Julian calendar, for the years 328 to 357, together with a list of dates of 14 Nisan in the Jewish calendar, also referred to the Julian calendar, for the years 328 to 343, the year of the Council. The calendrical information contained in the document has been used by scholars in tracing the history of the computus and of the Hebrew calendar.
The date of birth of Jesus is not stated in the gospels or in any historical sources, but most biblical scholars generally accept a date of birth between 6 BC and 4 BC, the year in which King Herod died. The historical evidence is too incomplete to allow a definitive dating, but the year is estimated through three different approaches:
Etymology: Medieval Latin, in the year of the Lord
anno aerae nostrae vulgaris
Herrmann observes, "The changes – showing up at museums, in academic circles and in school textbooks – have been touted as more sensitive to people of faiths outside of Christianity." However, Herrmann notes, "The use of BCE and CE have rankled some Christians"
The influence of western culture and scholarship upon the rest of the world in turn led to this system of dating becoming the most widely used one across the globe today. Many scholars in historical and religious studies in the West in recent years have sought to lessen the explicitly Christian meaning of this system without abandoning the usefulness of a single, common, global form of dating. For this reason the terms common era and before the common era, abbreviated as CE and BCE, have grown in popularity as designations. The terms are meant, in deference to non-Christians, to soften the explicit theological claims made by the older Latin terminology, while at the same time providing continuity with earlier generations of mostly western Christian historical research.
Part 3 has title: Tomi L Ephemeridvm Ioannis Kepleri pars tertia, complexa annos à M.DC.XXIX. in M.DC.XXXVI. In quibus & tabb. Rudolphi jam perfectis, et sociâ operâ clariss. viri dn. Iacobi Bartschii ... Impressa Sagani Silesiorvm, in typographeio Ducali, svmptibvs avthoris, anno M.DC.XXX.* Translation of title (per 1635 English edition): New Ephemerids for the Celestiall Motions, for the Yeeres of the Vulgar Era 1617–1636
Before Christ according to the Vulgar AEra, 6
reckoning it backward from the vulgar era of Christ's incarnationHumphrey Prideaux, D.D. (1716) [from Oxford University Press 1799 (1716 edition not online, 1749 online is Vol 2)]. The Old and New Testament Connected in the History of the Jews and Neighbouring Nations. Vol. 1. Edinburgh. p. 1.
This happened in the seventh year after the building of Rome, and in the second year of the eighth Olympiad, which was the seven hundred forty-seventh year before Christ, i. e. before the beginning of the vulgar æra, by which we now compute the years from his incarnation.
Dionysius the Little brought the vulgar era of the nativity too low by four years.
4 Apr. anno aerae christianae 1584
anni æræ Christianæ, 1649
Some say the World was created 3950 Years before the common Æra of ChristBefore Christ and Christian Era appear on the same page 252, while Vulgar Era appears on page 250
Common aEra chrift.Sale, George; Psalmanazar, George; Bower, Archibald; Shelvocke, George; Campbell, John; Swinton, John (1759). An Universal History: From the Earliest Accounts to the Present Time. Vol. 13. London: C. Bathurst [etc.] p. 130.
at which time they fixed that for their common eraIn this case, their refers to the Jews.
in the year of the world 3692, and 312 years before the vulgar era. ... The Spanish era began with the year of the world 3966, and 38 years before the common era (p63)
St Peter died in the 66th year of the vulgar era
This happened in the 33rd year of the common era, fome time after our Saviour's death.
the common era of the Jews places the creation in BC 3760A. Whitelaw, ed. (1874). Conversations Lexicon. The Popular Encyclopedia. Vol. V. Oxford University Press. p. 207.
Hence the present year, 1858, in the common era of the Jews, is AM 5618–5619, a difference of more than 200 years from our commonly-received chronology.Rev. Bourchier Wrey Savile, MA (1858). The first and second Advent: or, The past and the future with reference to the Jew, the Gentile, and the Church of God. London: Wertheim, Macintosh and Hunt. p. 176.
Its epoch is the first of March old style. The common era of the Mahometans, as has already been stated, is that of the flight of Mahomet.Johannes von Gumpach (1856). Practical tables for the reduction of Mahometan dates to the Christian calendar. Oxford University. p. 4.
It should be observed, however, that these years correspond to 492 and 493, a portion of the annals of Ulster being counted from the Incarnation, and being, therefore, one year before the common era of the Nativity of our Lord.James Henthorn Todd (1864). St. Patrick, Apostle of Ireland, A Memoir of his Life and Mission. Dublin: Hodges, Smith & Co, Publishers to the University. pp. 495, 496, 497.
Jews do not generally use the words 'A.D.' and 'B.C.' to refer to the years on the Gregorian calendar. 'A.D.' means 'the year of our L-rd,' and we do not believe Jesus is the L-rd. Instead, we use the abbreviations C.E. (Common or Christian Era) and B.C.E. (Before the Common Era).
Here is buried his honour Judah ben his honour Joseph, a prince and honoured amongst philanthropists, who executed good deeds, died in his house in the City of Bath, Tuesday, and was buried here on Sunday, 19 Sivan in the year 5585. In memory of Lyon Joseph Esq (merchant of Falmouth, Cornwall). who died at Bath June AM 5585/VE 1825. Beloved and respected.[19 Sivan 5585 AM is June 5, 1825. VE is likely an abbreviation for Vulgar Era.]
For dates, please use the now-standard 'BCE–CE' notation, rather than 'BC–AD.' Authors with strong religious preferences may use 'BC–AD,' however.
It has been said of the Latin words anno Domini, meaning in the year of our Lord ...
Marked by the turn of the Common Era, C.E., originally referred to as A.D., an abbreviation of the Latin Anno Domini, meaning 'Year of our God/Lord.' This was a shortening of Anno Domini Nostri Jesu Christi, meaning 'Year of our God/Lord Jesus Christ.'
'I find this attempt to restructure history offensive,' Lori Weintz wrote, in a letter to National Geographic publishers. ... 'The forward to your book says B.C. and A.D. were removed so as to "not impose the standards of one culture on others." ... It's 2006 this year for anyone on Earth that is participating in day-to-day world commerce and communication. Two thousand six years since what? Most people know, regardless of their belief system, and aren't offended by a historical fact.'
This practice [of BCE/CE] is the result of the secularization, anti-supernaturalism, religious pluralism, and political correctness pervasive in our society ... retention [of BC/AD] is a reminder to those in this secular age of the importance of Christ's life and mission and emphasizes to all that history is ultimately His Story.
To call our age 'the Common Era,' even though for the Jews, the Chinese, the Tamil, the Muslims, and many others it is not a common era, constitutes the acme of colonialism.
A.D. appears either before or after the number of the year ... although conservative use has long preferred before only; B.C. always follows the number of the year. ... Common era (C.E.) itself needs a good deal of further justification, in view of its clearly Christian numbering. Most conservatives still prefer A.D. and B.C. Best advice: don't use B.C.E., C.E., or A.C.E. to replace B.C. and A.D. without translating the new terms for the very large number of readers who will not understand them. Note too that if we do end by casting aside the A.D./B.C. convention, almost certainly some will argue that we ought to cast aside as well the conventional numbering system itself, given its Christian basis.
Certain abbreviations traditionally set in small caps are now in full caps (AD, BCE, and the like), with small caps an option.
Although A.D. (Anno Domini, meaning "in the year of our Lord") and B.C. (before Christ) are used in lands where professed Christianity predominates, we have chosen to use the terms C.E. (Common Era) and B.C.E. (Before the Common Era).