I've heard that
Queen Victoria was so revered, or something, was so out of reach anyway, that people didn't feel comfortable using her name, so used
Queenie instead. Then after QV's death it kept on being used in the UK and perhaps the colonies, though not so much.
DH had a (black South African) student once whose given names were
Queen Elizabeth. As far as he could tell, she regularly went by both; he found it embarrassing.
Somewhere in the
Anne of Green Gables stories, when she's a university student, she dates a guy who's known as
Roy but whose actual name is
Royal. I remember being greatly surprised when I read that!