George McDonald brought an original element in what we call fairy tale, the problem of gravity and of corse many other elements, which i would not point out because Adeline did. Many princesses have been cursed by witches, but here the story is different, the princess is cursed by her aunt, Princess Makemnoit. Than other unusual thing for a fairy tale, is the death of a character in order to save the condition of another. You have to die to be alive, to revive the sense of life. So did the Prince from "The Light Princess ".
