Page 19. " “So I was thinking maybe I would go to Italy and do something to provoke the Volturi.” "

  The Volturi are the rule enforcers of the vampire world. They were briefly mentioned in Twilight and are mentioned again at the start of New Moon as Edward reveals to Bella how he once considered going to the Volturi to ask them to kill him, when he thought she might have died at the hands of James. James was a sadistic vampire in Twilight who was set upon killing Bella. The Cullens managed to save her before he carried out his threat.