When was it decided that the calendar was going to switch from being BC to AD?

by ghastmaster2000

Also,when did people first start using BCE and CE instead of BC/AD?

brojangles

The BC/AD dating system was invented in the 6th Century by a Catholic monk named Dionysius Exiguus. There was no decision to go from BC to AD. That is a retrojected divide. The system wasn't developed until 535 and didn't start to be widely used until the 9th Century.

BCE/CE dates back at least as early as 1615, but started to be commonly used academically by Jewish scholars in the 1800s.