posted on Aug, 31 2009 @ 11:36 PM
A few clarifications...
Pope Gregory XIII adjusted the Julian calendar because of leap years. The Julian calendar had 1 leap year every four years, like the Gregorian
calendar, except the Gregorian calendar removed leap years at the beginning of centuries (except centuries dividable by 4). 2000 was a leap year; 1900
was not, neither was 1800 nor 1700. 1600 was.
Before the Gregorian calendar, and before it became widely adopted, years were, generally throughout history, calculated by reigns. For example, you
would talk about a specific event and say it happened in the 15th year of the reign of Augustus, or the 12th year of the reign of Tiberius, or 2nd
year of the reign of Caligula or 5th year of the reign of Claudius. That's all nice and well, except that if you don't know whether Claudius came
before of after Caligula of where Tiberius is in relation to all of this, it gets complicated.
Gregory's scientists put together a historical map of worldwide events in order to establish a date based on what was assumed, to the best of their
knowledge, to be the birth of Jesus. They used histories of Europe, the middle East and everything they could find. The date is probably wrong. It
makes more sense that this is something like 1655 rather than 2009, but that's a whole subject altogether...
So, in 36 BC, Romans would not have said "this is the year 36 BC" or -36 (they weren't Christians: nobody was at that time). They would have said
"This is the first year of the reign of Augustus".
Hope this helps.
Here's a Wiki on the Gregorian calendar: WIKI