Not having learned too much about the Roman Empire in school, I found out something totally brand new to me:
We sure did learn about Romulus and Remus... as I recall, we learned about them mythologically rather than historically. We learned about the Ides of March somewhat in the context of a Shakespeare play, but without having to read the whole play or even watch the movie. Brutus stabs Julius Caesar after he was already stabbed over 70 times, still lively enough to be sarcastic at the end, and that's why you should watch your back on March 15th. "All Roads Lead to Rome," the aqueducts. I seriously don't remember that we learned any more than that, as we had to move on to feudalism for a while and then WWI and WWII. They say the schools are really good there, but I feel like I might as well have been homeschooled, you know what I mean?
Anyway, this Ab Urbe Condita article mentions there was some douchebag in the 6th century (ACE, in retrospect) was trying to calculate the date of Easter and invented the AD calendar.
Yeah, I know, Easter is the first Sunday after the first full moon after the Vernal Equinox. Precision. I'm just trying to figure out why, if Jesus had existed as recently, that when I look up on Wikipedia every day or so to see what interesting events occurred or celebrated persons' birthday or National Go Fuck Yourself Day or whatever, at the top of the events are Roman events, to the precise date and year, BC, single and double and triple digit years. They didn't have someone calculating when Rome was created. 21 April 753 BC. It's given as a traditional date, but even wikipedia doesn't list Jesus Christ as having a birthday.
I know we talk about this "lost" record of Jesus, given how fastidious the Romans apparently were at record-keeping. Did they record the names of other prisoners and when they were executed? Ok. http://en.wikipedia.org/wiki/April_3 "33" Generally agreed-upon date of Jesus being crucified. Did the monk figure that one out? I realize I'm not blowing the lid off something new for most people.
He used it to identify the several Easters in his Easter table, but did not use it to date any historical event. When he devised his table, Julian calendar years were identified by naming the consuls who held office that year — he himself stated that the "present year" was "the consulship of Probus Junior", which he also stated was 525 years "since the incarnation of our Lord Jesus Christ". How he arrived at that number is unknown. He invented a new system of numbering years to replace the Diocletian years that had been used in an old Easter table because he did not wish to continue the memory of a tyrant who persecuted Christians.
For another thing, a calendar that was already in the 500s when it was invented.. Numbering the years somehow is a little important and general agreement is important, but every year that war on Christmas gets all the attention and then nobody even cares about New Year's. It wasn't even that long ago that people were calling it the year of our lord, in laws, on proclamations, invitations, diplomas, etc., as a matter of course. It's not worse, as things go, than "under God" or "In God We Trust." If we can just start a new calendar any time we don't want to commemorate the events precipitating the old one, though...