"it's two years from 1 BC to the start of 1 AD." You didn't say if that was from the start of 1 BC or the end of 1 BC. In either case, your just plain wrong.

You admit Zeno invented zero after the Gregorian calendar was created. In any case, we use zero all the time... to represent nothing. Which is what a person has to have between the ears to think the first year was numbered zero. Counting always starts with 1, not 0. A year is something, not nothing.

But then I see plenty of examples that people don't have to be smart to be happy. Have a happy holiday! <g>