1 BC

Anno Domini

Traditional Dionysian epoch assigned to the birth or incarnation of Jesus

The world's most familiar year-numbering system begins with a year its creator never explicitly identified as Jesus's birth year.

A date with no recorded day

No contemporary source records Jesus's birth in 1 BCE, in AD 1, or on a particular calendar day, so no sequence of events can be reconstructed for this assigned date.

The association is retrospective. Dionysius Exiguus introduced his anno Domini numbering in 525 while constructing Easter tables, rather than recording a birth he had dated from contemporary evidence.

1 BCE or AD 1: the epoch is disputed

Dionysius described 525 as years from the incarnation but never explicitly stated a calendar year for Jesus's conception or birth. Alden Mosshammer's reconstruction places the nativity implicit in the Dionysian era on 25 December 1 BCE; Georges Declercq and a recent reanalysis instead argue that Dionysius fixed the incarnation in AD 1.

The two readings are not interchangeable, and conventional BC/AD chronology has no year zero between them.

What the gospels leave out

The gospels themselves identify neither a year nor a date. The commonly cited modern estimate of roughly 6–4 BCE is a historical reconstruction, not a documented birthday, and 25 December is a liturgical date rather than one established by contemporary birth documentation.

The datable consequence belongs to the sixth century: in 525 Dionysius's Easter table introduced anno Domini numbering, whose wider adoption took centuries.

Sources

Researched 23 Aug 2026 6 sources 3 audit passes Date disputed

How this was checked

Researched from the web into a fact sheet, rewritten from that sheet, then audited against it by a different model. How the pipeline works →

Date disputed. Sources disagree; the research places it at -0001.

What the sources leave uncertain

The slug's date, −1, means 1 BCE, while its title begins “AD 1”; those are different years because traditional BC/AD chronology has no year zero.
Dionysius used “incarnation,” whose intended relation to conception and birth is debated, and he never explicitly wrote that Jesus was born in 1 BCE or AD 1.
Modern historical estimates commonly place Jesus's birth several years earlier, but the surviving evidence does not establish a precise year, month or day.
This is a calendrical attribution, not a securely dated historical event.