Board Thread:The Reference Desk/@comment-4139960-20130925182903/@comment-4139960-20130925192354

So at the very least, there's enough to say that she's royalty, even if none of what Smaller's picked up directly links to Charles. No idea if saying Diana, Princess of Wales is a breach of T:NO RW or not. I do understand plenty of political figures and famous people who are only identified by surname are given the full title at least for the sake of being easy to search.

And, apart from maybe the Roman goddess, she is a pretty famous Diana that's widely known as just Diana, especially in the British tabloids (from what I gather. I'm British, but not exactly newspaper reader.) However, it's not really the "every Diana character is her namesake" like with Victoria, so using it as the primary term is probably overstepping it.