I've been researching this one because my fiance is named Rhett. What I've learned is no one is sure where it came from or what it means but all agree the first person to ever use it was Margaret Mitchell and her novel Gone With The Wind was certainly the first place I ever saw it. Well after looking into the life of this woman I've come up with a theory of where it came from: if you pronounce every syallable of her name the last one sounds like Rhett. There was a man she was very close to named Henry Love Angel so that would explain where she got the H added to the syllable. Maybe she combined his first intial with the last syllable of her own name to form Rhett. It could have even been some kind of message to this guy. I'd love to get some feedback on this theory.