Its about B.C. and A.D. We all know B.C. is before and A.D. is after....?

So there must be a zero day or a moment when the B.C. ended and A.D. started. But my question is, we know lot of history which is known to us in B.C. years, now how can one decide that its 400 B.C. when is was happened even before the calculation started. Was there any other way of keeping track of the dates before putting this new dating system as B.C. and A.D. How was the events and dates which was happened before 1 A.D. connected to the new system as B.C.

Its about B.C. and A.D. We all know B.C. is before and A.D. is after....?
There are even today many different ways of figuring out time. For example this weekend, on 29th Jan the chinese new year starts. It is Year 4703 by the Chinese calendar. And it is the jewish year 5677.


And even the christian calendar has been modified a couple of times. The gregorian calendar reform was adopted in 1582 but not in England and so also not in the US, they only changed in 1752 (so they lost 11 days).


Which year we are in is only relative to what you want to measure. If you want to be more explicit you don't just say B.C. (Before christ) but B.C.E (before the christian era). As long as you can figure out how far apart they are you can easily convert one into the other and allow for changes.


For time of the year (month/day) it is probably best to go by a system like now, which is constant with and corresponds to the seasons of the year. So while George Washington was born on the 22nd feb 1732, his parents must have thought it was the 11th when he was born.


I don't know how far historic dates get modernized to reflect calendar changes.
Reply:Anno Domini = The year of the Lord.
Reply:because we refer to it as that year, at least in the christian world, in the jewish calender it is the year 5766 so, no b.c or a.d. applies
Reply:midrash40 did not state that there was no dating system before Christ. He made two seperate statements In the Christian world we use A.D. and B.C. I believe this is from the Juliene system.(not sure of spelling). In the Jewish dating system they don't recognize Christ, so their calendar does break around Him. They have a certain start date and have just continually counted up from there.
Reply:The reason we started marking years to begin with is because we started to look forward to the second coming of Christ, which is what the BC/AD thing is based on. Before Christ was born, no one cared WHAT year it was, but that a year HAD passed. AD is every time after Christ's final 40 days on Earth. BC is every time before he was born. Between that is BCE or Before Christ's Execution, and there are 34 years BCE. So, to officially answer, no, there isn't a zero day, the modern dating system is the invention used so we know when Christ will come back, and the years we call BC were unmarked years (hence the (?) or "approx." you'll see if you look up a name in a dictionary.) So there was never a dating system before the BC/BCE/AD thing. Blame it on eagerness to find out who's going to Heaven, really.
Reply:B.C. means "before Christ"


A.D. is from the Latin word "anno Domini", meaning "in the year of our Lord."