Yes I am aware that there has been calendar shifts and relocations of events for prior cultural reasons etc.
But none of that negates the validity of my question.
Which if I might re-phrase:
If someone were to write down the date of the 27th December being two days after Christ was allegedly born, is it written 27th Dec 1 AD, or is it 27th Dec 1 BC or is it something else and if so what?
Unless Jesus was alleged to have been born at the stroke of midnight on 31st Dec/1st Jan, then there will be a window where that AD/BC confusion exists.
I just wondered if there was some recognised way of indicating times within that window.
I would presume, that it would be written 27Dec 1 BC, even though it technically was not BC.