Well, at the time 'ol Yehsua bar Joseph popped in, years in some places were measured by reigns. Rome measured in the time from the city's founding (AUC, or, uh...my Latin's not that good, but something like Anno Urbanis Civitas...Latin types, please correct...;) By the Dark Ages, no one was seriously measuring dates at all...;)

Actually, it was the Russians that were the last holdouts on the current calendar system; we started with the current one in 1776, and the Russians in 1917...;) People were fit to be tied; they 'lost' 23 days...;)  The current calendar system makes every 4 centuries' last year a leap year (so unless you're alive some time after Star Trek Voyager, you won't see the next one...;)

The Christian calendar didn't officially 'cement' until the 6th Century or so (not long before the Muslim Year of the Hejira..) There were knock-down dragouts about when to celebrate Easter (this was a real thorn to the Venable Bede...whomever he was...;) They just sort of 'lined up' the last date that Easter was celebrated on the same date, loosely checked to see if it fit the Gospels, and according to modern calculations, Jesus was born about 4BC...;) talk about ahead of your time...;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)