I'm thinking of the Persian dynasty for example. Darius The Great ascended in 522(?) BCE - but people living in that time obviously didn't call their years "522 BCE" ("what happens when we get to 0!?").
So... How did they refer to years then? Did it change from Egyptian to Greek to Persian to Macedonian to Roman... or...? How about the far east (China)? Or how about NA?
There's always room for discussion, but perhaps the section Calendars and timekeeping from our FAQ will answer your inquiry.