yeah, so it turns out that a long time ago when people started documenting dates of history and making a timeline, they messed up. Jesus Christ was supposedly living during a time when this one king(dont know the name) was ruling. Well, it turns out that this king died somewhere between 6 BC- 4 BC. How could he die before christ if christ was alive? yeah so its actually somewhere between 2002-2004. Weird, huh? I asked my theology professor about it and he confirmed. i just find this crazy
There were actual several times throughout history that authorities have just decided to change the date because calendars weren't "meshing up" properly. This happened on several occasions when it would be like Monday, June 14 and the next day was like Tuesday, June 30. Ridiculous stuff like that has happened throughout time as calendars developed from a state of extreme imperfection.
Thats why you hear people say "circa ___" because even if the date is down to a certain day, the calendars are screwed up and they're really not sure how accurate it is.