anno Domini

In the Christian chronological system, refers to dates since the birth of Jesus, denoted by the letters AD. There is no year 0, so AD 1 follows immediately after the year 1 BC (before Christ). The system became the standard reckoning in the Western world after being adopted by English historian Bede in the 8th century. The abbreviations CE (Common Era) and BCE (before Common Era) are often used instead by scholars and writers as objective, rather than religious, terms.

The system is based on the calculations made 525 by Dionysius Exiguus, a Scythian monk, but the birth of Jesus should more correctly be placed about 4 BC.