How are the years before and after year zero labeled on the Gregorian calendar?
On the Gregorian calendar, years before year zero are labeled B.C., meaning Before Christ, while years after are labeled A.D., from Latin Anno Domini, meaning “year of our Lord.” Some now replace these with B.C.E. (Before Common Era) and C.E. (Common Era).
Les explains that A.D. comes from the Latin words Anno Domini, where Anno gives us “annual” and Domini means Master or Lord. So A.D. stands for “the year of our Lord,” which on the Gregorian calendar is year zero. From year zero backward, everything is referred to as before Christ (B.C.), and forward as the year of our Lord (A.D.). Les notes that modern scholarship has changed these nomenclatures: B.C. becomes B.C.E. (Before Common Era), and A.D. becomes C.E. (Common Era). He says he does not know where “Common Era” comes from, but this is what is now being done, reflecting an effort to remove Christ from the picture.