The termante Christum natum[1] (Latin for 'before Christ [was] born'), usually abbreviated toa. Chr. n.,a.Ch.n.,a.C.n.,A.C.N., orACN, denotes the years before the birth ofJesus Christ.[2] It is a Latin equivalent to the English "BC" ("before Christ"). The phraseante Christum natum is also seen shortened toante Christum ("before Christ"), similarly abbreviated toa. Chr.,A. C. orAC.[3][4][5] A related phrase,p. Chr. n.,p. Ch. n.,P.C.M,PCN, orpost Christum natum complementsa. Ch. n. and is equivalent toAnno Domini (AD).[6]
In English, these phrases are rare and AC, ACN, andante Christum natum are not in theChicago Manual of Style (14th edition), theAmerican Heritage Dictionary (3rd edition), or P. Kenneth Seidelmann'sExplanatory Supplement to the Astronomical Almanac (1992, University Science Books). In other European languages, such as Italian ("a.c." or "a.C." foravanti Cristo), a vernacular version is the standard term.
TheAnglo-Saxon historianBede used the Latin phraseante incarnationis dominicae tempus ("before the time of theIncarnation of the Lord") in hisHistoria ecclesiastica gentis Anglorum (Ecclesiastical History of the English People) (Book 1, Chapter 2) of 731 PCN, and thereby became the first author to describe a year as beingbefore Christ.[7] BothDionysius Exiguus and Saint Bede, who was familiar with the work of the former, regarded Anno Domini 1 as beginning on the date of the Incarnation ofJesus Christ, yet "the distinction between Incarnation and Nativity was not drawn until the late 9th century, when in some places the Incarnationepoch was identified with Christ's conception, i. e., theAnnunciation on March 25".[8]