As far as I know, I didnt do anything. Actually its not the barbarian race, its Barbarian of America. ie Sid Meier's name is Barbarian and the leader of the Americans. He has to be bugged as well as I get no + or - diplomacy mods against him and he requests pretty much the same thing every turn.
edit: In the espy screen, he shows as Genghis, I attached a save file.