Column–
Prince Andrew has become the first British royal to join Twitter. His account will be a mixture of tweets from him and his staff. But here’s the interesting part–tweets from him will bear the initials “AY”–“A” presumably stands for Andrew. The “Y” must stand for York; I can’t think of anything else it could mean. Which must mean that he’s using York as sort of an unofficial last name.
http://www.people.com/people/package/article/0,,20395222_20715162,00.html
Easier than signing off “PAoY” or “APoY”.
Not unheard of: isn’t Prince Harry’s military name “Harry Wales”?
(Actually, I used to be a stickler for calling him “Prince Henry”, but once The Times and the BBC made the switch, I figured that it was about as close to an “official endorsement” of the name as we could get, and yes, I know that The Times is owned by Rupert Murdoch.)
Noblemen in general use their titles as last names, although, unlike the royal family, they have undisputed last names, too.
An earlier related thread: What did Prince Andrew's superiors in the Royal Navy call him? - Cecil's Columns/Staff Reports - Straight Dope Message Board
And the British upper classes use their last names as given names. At least they did when I was in school.
According to anecdote (I can’t find a reference) as a young man Edward VII was heard asking his brother 'York, have you seen the bloody monarch?"
I think you mean Edward VIII, whose younger brother was Duke of York (and later King George VI). Edward VII’s brothers were Prince Alfred, Duke of Saxe-Coburg and Gotha, and also Duke of Edinburgh; Prince Arthur, Duke of Connaught and Strathearn; and Prince Leopold, Duke of Albany.