Classically trained stage actor, got famous doing cheesy horror movies, which gave him the exposure to do the sort of roles he actually wanted to do. One of the most prolific actors ever, capable of the levels of gravitas generally recognized in gods and madmen.

Plus, he was an actor who played villains who is known to have actually killed people, and knew what it was like to do so. He was Ian Fleming's cousin and a spy in World War 2, as well as actual Italian nobility. There won't be many actors like him going forward. Actors are no longer more interesting than the characters they play.

go read his wikipedia page, it's amazing. Does he have a full bio published?