The Norman-Swabian castle is crowned by four towers, one of which is called St Francis' tower because it is said that the saint stopped here on one of his pilgrimages. Legend has it that he was invited to one of the many feasts held in the building, but only ate a piece of bread. Then the emperor decided to test his purity and, given the late hour, invited him to rest in one of the towers. Then he arranged for a beautiful girl to wait for him, who wanted to spend the night with him. But Francis, in order to thwart the desire, gathered a pile of coals from the fireplace and invited the young girl to lie down with him on the improvised bed. The emperor was so impressed by the gesture that the next day he dismissed the saint with words of praise and esteem.