Brittanica.com says about historical novel:
"a novel that has as its setting a usually significant period of history and that attempts to convey the spirit, manners, and social conditions of a past age with realistic details and fidelity (which is in some cases only apparent fidelity) to historical fact. The work may deal with actual historical characters...or it may contain a mixture of fictional and historical characters"
Yes, if a novel contains historical setting (background - time and place), like a part of history that really ever happened or a really existed historical figure, it is a historical novel.
I am one of the fans of this kind of book/literature/film. I'm fond of history since I was a kid, my mom or my grandma had told me various yet amazing stories. Even until now, my favorite moment is when I listen to someone talking about chronicles of something, someplace or someone. I listen like a good student :D The thing is, I want to know a lot more information about what had happened in a certain time at a certain place with a famous people, that's actually one of the reasons why I choose to study German Literature, German has a great history, who doesn't know about Prussia and Alexander the great? Who doesn't know Hitler and NAZI? Well, I know a lot more about it :p
I love to learn history from novels or films because I didn't even realize that I am learning something, so it's really enjoyable yet entertaining, and I would start to google or find articles about it and compare the real event and those which happened in the book or film. Here are 10 amazing historical novels/roman: