0 is a year if we say it is, which astronomers have for hundreds of years (because its extremely mathematically convenient), and which ISO-8601 does. Year 0 is

0 is a year if we say it is, which astronomers have for hundreds of years (because its extremely mathematically convenient), and which ISO-8601 does. Year 0 is what historians like to call 1 BC, but historians are also just making that up. Nobody numbered years from Anno Domini anywhere near year 0. I'm sure it's clear to everybody here why year 0, -1, and -2 are significantly better arbitrary, ahistorical names for the three years preceding year 1.