Jesus was probably born “Before Christ”
The AD system was invented in 525 by a monk who got the date slightly wrong. Most historians place Jesus’s birth around 6–4 BC.
In 525, in Rome, a monk named Dionysius Exiguus (“Dennis the Small”) was producing tables for calculating Easter. The existing tables counted years from the reign of the emperor Diocletian, a persecutor of Christians. Dionysius preferred to count from the Incarnation: Anno Domini, “in the year of the Lord”.
Slow to catch on
The system stayed obscure until the English monk Bede used it in his Ecclesiastical History of the English People (about 731). From there it spread across Europe and, much later, the world. The neutral labels CE and BCE (Common Era) use the same numbering.
No year zero
Dionysius worked before the zero reached Europe, so the count goes straight from 1 BC to AD 1. That’s why the third millennium technically began on 1 January 2001, not 2000, a point pedants enjoyed making at the time.
A small miscalculation
The Gospel of Matthew places Jesus’s birth during the reign of Herod the Great, and historians date Herod’s death to around 4 BC. So most scholars put the birth at about 6–4 BC. Nobody knows exactly how Dionysius arrived at his figure. It just appears to have been a few years off.
Bring it up
“By the calendar’s own logic, Jesus was probably born a few years ‘Before Christ’.”
Follow the thread
- RelatedWhy Christmas is on 25 December Both the day and the year of the nativity were worked out centuries after the event.
- RelatedFibonacci’s real legacy wasn’t the sequence The lack of a year zero reflects arithmetic before zero reached Europe.
- RelatedCleopatra lived closer to the Moon landing than to the pyramids BC dates count down, which makes comparing ancient timelines harder than it looks.
- RelatedWhy Ramadan moves about 11 days earlier every year Calendars count from founding events: the Hijra in 622, or the Incarnation.
