Understanding A.D. and B.C.: A Brief History and Explanation

Understanding A.D. and B.C.: A Brief History and Explanation

We are nearing the end of 2024 A.D., marking the years since the birth of Jesus Christ. However, this system may have an error in its foundation as the birth of Christ is believed to have occurred between 6 and 4 B.C.

What Do A.D. and B.C. Stand For?

A.D. stands for Anno Domini, which translates to in the year of the Lord. B.C. stands for Before Christ.

The Absence of Year 0

In the context of this dating system, there is no year 0. The year immediately before the birth of Christ is 1 B.C., and the year immediately after is A.D. 1.

The Origin of A.D. and B.C.

The concept of A.D. and B.C. has its roots in the work of Dionysius Exiguus, a Roman monk who invented this system in 525 A.D. Exiguus chose the birth of Jesus Christ as the reference point, creating an era of counting years from this event (A.D.) and backward (B.C.).

Dionysius Exiguus' Latin terminology was explicitly defined as Anno Domini, meaning in the year of the Lord, and not After Death as some people incorrectly assume.

Moving Towards a More Inclusive Terminology

To make the system more inclusive and neutral, the terms Common Era (CE) and Before Common Era (BCE) were introduced. Both terms are numerically equivalent, with the same numerical values as A.D. and B.C.

Key Takeaways: A.D. stands for Anno Domini (in the year of the Lord). B.C. stands for Before Christ. There is no year 0 in the A.D. and B.C. system. 1 A.D. is immediately preceded by 1 B.C. Common Era (CE) and Before Common Era (BCE) are used to make the system more inclusive.

Further Reading: The Evolution of the Calendar

For a deeper understanding of how the calendar has evolved over history, including the invention of leap years, the definition of months, and the role of politics in calendar development, read our illustrated story of calendar evolution.