Los escarpines de Kristina de Noruega / The Slippers of Kristina of Norway

Beatrice of Swabia in labor pain, stops her horse and before giving birth, buries the baby's socks-and the secrets they contain. The child who comes into the world is the future Alfonso X the Wise. Years later, when Princess Kristina of Norway comes to marry Alfonso, she shall have the socks. How is it possible? what mystery contain them?