Ish can you tell me why Elizabeth was "of York"? Is it because her father inherited the title, Duke of York, after his father was killed, before he became King? But Elizabeth was born when he was King so should she have been Elizabeth of England?
You bring up a really interesting question here, and I'm not certain of the answer.
Women were typically "of" something in relation to their father - if their father held no titles, and was just "of" wherever he came from then it would be that, but if he held titles then sometimes it would be "of" the title and sometimes it would be "of" where he came from. Daughters of the king were usually "of" the kingdom, but sometime that just depended on when they were born and when they were married (in comparison to when their father became king). I'm not sure if an unmarried woman at the time would have changed her "of" to reflect her father's status, as happens now.
That said, the trick with Elizabeth becomes a matter of when she became "of York." It could be that she was "of England" when born, but "of York" when her father was deposed, and just retained it after he became king again (not likely, as all of Edward's daughters are known as "of York").
It could be that they became known as "of York" when Richard came to the throne and declared them illegitimate - in this way they would have been taking a more noble surname than the "FitzRoy" more commonly associated with acknowledged illegitimate children.
It could also be that "of York" is more of a historical name - as time passed we recorded he surname as being of her father's house rather than what she actually used at the time. I do know that this is often the case when "Plantagent" is used.
They didn't use this modern system at all. Richard's son was Edward of Middleham - he was born at Middleham Castle. Real power and lands were more important than titles.
Real power and lands were often denoted by titles. The "of wherever" as a surname typically denoted where a
man was born, but not a woman. Elizabeth is a perfect example as she wasn't born in York, but London.