Keeping time: The origin of B.C. and A.D.

The use of "anno domini" and "before Christ" to mark time began in the early days of Christianity, when clerics needed to know when Easter would fall.

Keeping time: The origin of B.C. and A.D.
The use of "anno domini" and "before Christ" to mark time began in the early days of Christianity, when clerics needed to know when Easter would fall.