Ante Christum Natum
Ante Christum Natum (Latin for Before Christ (was) Born), usually abbreviated to A.C.N., a.C.n., a.Ch.n. or ACN, denotes the years before the birth of Jesus Christ. It is the modern Latin equivalent to the English term "BC" ("Before Christ"). The phrase Ante Christum Natum is also seen as the shorter Ante Christum (Latin for "Before Christ"), again usually abbreviated to A.C. or AC. A related term, p.Ch.n or post Christum natum complements a.Ch.n and is equivalent to "AD".
These terms are chiefly found in modern Latin texts. English speakers are unlikely to recognize them. Neither the Chicago Manual of Style (14th ed.), the American Heritage Dictionary (3rd ed.), nor P. Kenneth Seidelmann's Explanatory Supplement to the Astronomical Almanac (1992, University Science Books) mention AC, ACN, or Ante Christum Natum.
These terms were not used in medieval and Renaissance Latin texts. Bede the Venerable, who was the first writer to identify a year as before Christ, used the Latin ante incarnationis dominicae tempus (before the time of the Incarnation of the Lord) in his Historia ecclesiastica gentis Anglorum (I.2) in 731. Most comparable early Latin terms referred to Christ's Incarnation or conception, not his birth nine months later.
- British Library manuscripts catalogue
- General Chronology in the 1913 Catholic Encyclopedia
- Webster's New World College Dictionary, Fourth Edition
- Webster's Ninth New Collegiate Dictionary (1983)
- Example from LogosLibrary.eu.