The Light Princess Description:

Quote, "So perfectly like other people had she been in the water, that even yet the prince could scarcely believe his eyes when he saw her ascend slowly, grasp the balcony, and disappear through the window. He turned, almost expecting to see her still by his side. But he was alone in the water. So he swam away quietly, and watched the lights roving about the shore for hours after the princess was safe in her chamber. As soon as they disappeared, he landed in search of his tunic and sword, and, after some trouble, found them again."