What does BC and AD mean?

BC and AD are two terms used to identify calendar dates. The letters stand for Before Christ and Anno Domini, which are Latin phrases meaning “before the Christian era” and “in the year of our Lord,” respectively.

History of BC and AD

The BC and AD format for identifying dates is believed to have originated with the monk named Dionysius Exiguus circa 527 AD. Dionysius’ system of reckoning was started in order to establish a centralized Christian calendar, where events in Christ’s life and religious feasts could be more easily tracked. This was also an attempt to add structure to the practice of dating various events.

Prior to this, other systems of dating events commonly included counting years in relation to the reign of a particular ruler or dynasty, including in Greece and Rome. In around 1551 this system of assigning calendar dates standardized further when the French Catholic scholar Joseph Justus Scaliger proposed using counts of years Before the Incarnation and After Christ’s Birth for religious and historical purposes.

What is the Difference between BC and AD

The main difference between BC and AD is that BC stands for “Before Christ” and AD stands for “Anno Domini”, which is Latin for “in the year of our Lord”. BC is used to identify dates prior to the time of Christ’s birth, whereas AD is used to identify dates after this time. The calendar which we currently use is based on the supposed date of the birth of Christ, and so as a result years after his birth use the AD format.