Anno domini system of dating
system gained in popularity in the ninth century after Holy Roman Emperor Charlemagne adopted the system for dating acts of government throughout Europe. The alternative form of “Before the Common Era” and “Common Era” dates back to 1715, where it is used in an astronomy book interchangeably with “Vulgar Era.” At the time, vulgar meant “ordinary,” rather than “crude.” The term “Vulgar Era” is even older, first appearing in a 1615 book by Johannes Kepler.
The system's inclusion was implicit in the 16th-century introduction of the Gregorian calendar, and it later would become an international standard in 1988 when the International Organization for Standardization released ISO 8601, which describes an internationally accepted way to represent dates and times.
But once they are in place, a firm framework exists for recording subsequent events.
By the 15th century, all of Western Europe had adopted the B.
But this does not make the new chronology any less useful for dating subsequent events, once the chronology is widely used (a process which takes some time to achieve) you have a firm framework.
Although the dating system was devised in 525, it wasn’t widely used until after 800,and even after that, other systems were still widely used throughout Europe.
Using earlier tables, he concluded that Jesus Christ was born in the Roman year 753 AUC (see ‘Other Chronology systems’ below). The start of the Christian era, like the founding of Rome, is not agreed until many centuries after the event.
He therefore proposed that the Christian era begins at the start of the following year. Such post facto chronologies are of little use for previous history.