AD (Anno Domini)

Anno Domini (525- ), or AD for short, is Latin for “in the year of the Lord”, meaning since the birth of Jesus Christ. It is how years are numbered in the Gregorian calendar, the main calendar used in the West. AD is also known as CE for the Christian or Common Era.

BC: Years before Christ are marked “BC” for “Before Christ” or BCE for Before the Common Era. BC counts down the years to the birth of Christ, so 13 BC comes after 14 BC. Some use a negative number instead, as in “Aristotle was born in -384.”

There is no year zero. The year before AD 1 is 1 BC.

When a year is given by itself in English, as in “Shakespeare was born in 1564”, the Christian Era is assumed.

To name a range of years, add an “s”: The 1960s means from AD 1960 to 1969. The 1900s, since it has two zeros, means from 1900 to 1999 – unless it is otherwise clear that only the ten years from 1900 to 1909 are meant.

Sample dates:

• -1323 death of King Tut
• -480 Battle of Thermopylae
• -384 birth of Aristotle
• -31 Battle of Actium
• 622 Hegira
• 1054 Crab Nebula supernova
• 1492 Columbus arrives in the Americas
• 1564 birth of Shakespeare
• 1969 Neil Armstrong lands on the Moon
• 2006 now

The starting year of other eras:

• -5509: anno mundi – Byzantine – creation of the world
• -5493: anno mundi – Alexandrian
• -3761: anno mundi – Jewish
• -3114 Mayan Long Count begins
• -2016: anno Abrahami – birth of Abraham
• -776; Olympiads (periods of four years) – from the first Olympics
• -753: AUC – anno urbis conditae – the founding of Rome
• -312: Seleucid – start of the empire
• +622: AH – anno Hegirae – After the Hegira – Muslim (the years are 354 to 355 days long)

Greek historians used Olympiads from -250 to +450. In 813, Theophanes used the Alexandrian Era, in use since 412. A corrected version of that, the Byzantine Era, was used by the Orthodox Church from 691 to 1728.

Josephus in the 90s used Seleucid years and Olympiads.

Eusebius and Jerome in the 300s used anno Abrahami.

Dionysius Exiguus in Rome invented AD in AD 525 – not to name years but to work out the date of Easter, which is different every year.

Isidore of Seville in Spain in the 600s numbered years from the conquest of Spain by Augustus in -38.

Bede in 731 was the first to use AD and BC in writing about history. AD did not start catching on till Alcuin and Charlemagne pushed it in the 800s; BC not till the 1600s!

Kepler in 1615 called the Christian era vulgaris aerae, meaning the vulgar or common era, as opposed to one that used the reigns of kings to date years, which the Bible uses.

When the abbreviations first appeared in English:

• 1570s: A.D.
• 1823: B.C.
• 1838: C.E.
• 1881: B.C.E.

A.C., for Anno Christi, was common in the 1600s.

Before the 1800s, no one in English said, “Aristotle was born in 384 B.C.” That is how new it is.

CE was first used to write Jewish history. It started to catch on among US scholars in the 1980s. It is now used about a fifth of the time in English-language books.

So was Jesus born in AD 1? No. He was born under King Herod, who died in -4. Most likely he was born in -6 or -7.

– Abagond, 2006, 2022.

See also:

• What year is it? – for time travellers and coma patients. Does not work if you are travelling near the speed of light. Or if your computer is set to the wrong year!
• Dionysius Exiguus
• Gregorian calendar
• Jesus Christ
• Easter
• Olympiad
• Isidore of Seville
• Kepler
• style guide: writing numbers
• geography