What is year of our lord?

The term "Year of Our Lord" (abbreviated as "AD" or "A.D.") is used to indicate that a calendar year falls within the Christian Era, which is measured from the birth of Jesus Christ. The practice of using this term dates back to the 6th century and was first introduced by a monk named Dionysius Exiguus.

The Year of Our Lord system is based on the Julian calendar (named after Julius Caesar) and was later replaced by the Gregorian calendar (named after Pope Gregory XIII) in the 16th century. In this system, the year 1 AD is the year in which Christ was assumed to have been born, although the exact year is unclear.

Today, the Year of Our Lord system is used primarily in Christian cultures and is often used interchangeably with the Common Era (CE) or Current Era (CE), which is a non-religious alternative to the AD system. However, the use of the term "Year of Our Lord" continues to be a common way of referencing historical events that took place within the context of the Christian tradition.