Year dating conventions can be defined as using the birth of Christ as a reference point, the dating system of B.C. (Before Christ) and A.D. (Anno Dommini or Medieval Latin for “in the year of the Lord”) have been used in the West since the Middle Ages. In deference to the non-Christian world many now use the designation B.C.E. (Before the Common Era or Before the Current Era) and C.E. (Common Era). B.C. dates = BCE dates; AD dates = CE dates. BP (Before Present) is a dating system widely used in Anthropology, YA (Years Ago) less often. 4,000 BP = 4,000 YA = 2,000 BCE = 2,000 BC.
Definition