How was the date recorded/understood before 525 AD when BC/AD was introduced? | AskHistorians Archive Observer

How was the date recorded/understood before 525 AD when BC/AD was introduced?

by Toni173

For example, what year did people think they were living in in 524 AD, before our current way was introduced?

How did the Romans work out that when they brought this in it was the year 525 AD?

doctorwhodds

While none specifically address the year 525 AD, there are numerous questions in the FAQ that address calendars.

Also, an early episode of the AskHistorians Podcast was titles: "How did we decide what year it is?"