Topic summary
Before Christ

Extracted from the Wikipedia article Anno Domini.
Popularization
Although anno 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. In 1627, the French Jesuit theologian Denis 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.