Does the name Jonathan Gilbert sound familiar to you? If it doesn't then clearly, you're not a fan of The Vampire Diaries. The show has made frequent references to Jonathan, who happens to be Elena and Jeremy's direct-line ancestor and an author/investor in Mystic Falls back in 1864.
I don't really know the mystery behind Jonathan and his journals (which Jeremy is currently using as reference for his history paper) or if he's even related to Elena considering the big revelation in last week's episode. But I'm sure we'll get more dirt on Jonathan as The Vampire Diaries treats fans with more flashback episodes.
According to Fancast.com, Jonathan Gilbert will be played by Joe Knezevich, who will make his Vampire Diaries debut in the episode "Children of the Damned," which is expected to air on February 4. Knezevich is an actor from Atlanta whose credits include Drop Dead Diva, The Librarian 3: The Curse of the Judas Chalice and One Tree Hill.