The Vow of Friendship, written in Italian, carved inside pocket watches that Giotto, and all of the First Generation Vongola Guardians possess, each with their respective Flame. For some reason, all of the watches appear to be stopped at 12:04. In the Manga, behind the lid of Daemon's pocket watch doesn't have the vow engraved as in the Anime, instead there's a picture of Giotto and the other Guardians with Elena, Daemon's lover (Though, it's possible that the words might be covered by the photograph).