I've often wondered why, here in the UK, our tax year starts on 6th April.
After having checked out the Wikipedia article on the Gregorian Calendar, I have the answer.
25th March was traditionally New Year's Day here in Britain, so the tax year, naturally, began on the same day. Then, in 1752, we adopted the Gregorian Calendar. 25th March magically became 5th April! Then it gets confusing... A 12th skipped Julian leap day in 1800 changed its start to 6 April. It was not changed when a 13th Julian leap day was skipped in 1900, so the tax year in the United Kingdom is still 6 April.
It's not clear when we adopted 1st January as New Year's Day.
I thought this was really interesting. Imagine, no-one here in the UK would have had a birthdate of, for example, 28th March 1752!
This leads to all kinds of weirdness. Was 20th April 1394 really 20th April 1394 or was it 9th April? Or was it 1st May? See, now I'm confused! Are you, dear reader?
This would be a fabulous basis for a Doctor Who story. The TARDIS materialises in London. The on-board calendar tells The Doctor and Martha that it's 2nd April 1752. Everything seems fine at first, but of course, it isn't...!
And do we celebrate pre-1752 dates in their Gregorian or Julian form?
Why are we here?
What's the meaning of life?