Asklemmy

I’m no expert but I assume that the year Christ died would be “year zero” (assuming you’re talking about anno Domini (AD) and before Christ (BC)) since we started counting after that.

EDIT: reading more on the topic I might be completely incorrect with my above statement. If someone else knows, please do correct me

EDIT 2: I found this on Wikipedia which talks about a “year zero”

It depends which calendar you use! Every calendar picks a basically arbitrary system to uniquely identify each year, and in some of them "year 0" doesn't refer to any year.

The Gregorian, for example, goes directly from 1 BC to 1 AD, since 1 BC is "the first year before Christ" and 1 AD is "the first in the years of our lord." This doesn't make much mathematical sense, but it's not like there was a year that didn't happen--they just called one year 1 BC, and the next year 1 AD.

ISO 8601 is based on the Gregorian calendar, but it includes a year 0. 1 BC is the same year as +0000; thus 2 BC is -0001, and all earlier years are likewise offset by 1 between the two calendars.

When you consider the time as a number line, years are not points at integers (which would in some way warrant a year 0), but rather periods between them. Year 1 is the period between 0 and 1, and before that was -1 to 0, or year -1. There is no year 0, because there isn't anything between 0 and 0