Anno Domini (Latin): "In the year of our Lord" which is an abbreviated form of the original Anno Domini Nostri Iesu Christi. It is often abbreviated as "A.D."
A method of marking time using the number of years since the birth of Jesus Christ. The years before the birth of Christ are designated "Before Christ", or "B.C." This system was developed in the 525 (by the same calendar) but was not widely adopted until the 8th century.
Interestingly, due to the inaccuracies of historical record keeping from that period, Christ is now thought to have been born in the year 2 C.E. by our calendar.
- A.S. - Anno Societatis