> it doesn't make any sense. According to who? The year numbering in the current western calendar starts from one (AD 1), not zero (it jumps from 1 BC to AD 1)

> it doesn't make any sense. According to who? The year numbering in the current western calendar starts from one (AD 1), not zero (it jumps from 1 BC to AD 1). So the first decade would be from AD 1 to AD 10, the second decade from AD 11 to AD 20, and so on (and the same on the other direction, with a decade from 10 BC to 1 BC, another one from 20 BC to 11 BC, etc).