Probably worth noting that the Gregorian Calendar was an invention of the 16th Century. It was invented to deal with the problems of the Julian Calendar and the creators would have had a firm understanding of the concept of zero. The AD/BC split was all about the assumed year of the birth of Jesus of Nazareth (according to Christian mythology). The year of his birth was set as the first year Anno Domini or “The year of the Lord”. Or the first year where Jesus was kicking about. The year prior to that would therefore be the first year before “Before Christ” was alive, and therefore the year 1 BC.
Probably worth noting that the Gregorian Calendar was an invention of the 16th Century. It was invented to deal with the problems of the Julian Calendar and the creators would have had a firm understanding of the concept of zero. The AD/BC split was all about the assumed year of the birth of Jesus of Nazareth (according to Christian mythology). The year of his birth was set as the first year Anno Domini or “The year of the Lord”. Or the first year where Jesus was kicking about. The year prior to that would therefore be the first year before “Before Christ” was alive, and therefore the year 1 BC.