Yet though Bertalda was sad, she was a wise maiden, and she received Undine kindly, thinking that she was a princess whom Huldbrand had rescued from a wicked wizard. For the true story of the beautiful Undine was known to none, save to the knight alone.
As for Undine, she no sooner saw Bertalda than she loved her, and begged her to stay in the city until she and her husband left it. Nay, more, she even asked the maiden to promise to go with them when they set out for the castle of Ringstetten, which stood on the banks of the river Danube, and Bertalda was well pleased with this request.
One evening they three together walked up and down in the public square. In the midst of the square stood a beautiful fountain, and here they lingered to watch the water as it tumbled and tossed. So violently did it do this that it seemed as though the fountain must break, and the water, bursting its bonds, must flow away far and free.
At that moment a tall man came towards them from the market-place, and, bowing to the knight and Bertalda, he drew the young wife aside that he might speak to her alone.
Huldbrand looked at the stranger, and as he looked he felt sure that he had seen him before. He grew a little angry, this hasty knight, as he watched his wife and the stranger whispering together. He caught a few words too, and they seemed to him to be in a foreign language, and this displeased him yet more.
At this moment, however, Undine left the stranger. As she came toward her husband she was laughing merrily and clapping her hands.
But the stranger, as she left him, shook his head and frowned. Then he walked with great strides toward the fountain, and stepping into it he vanished and was seen no more.
'It is Kühleborn, the spirit of the forest stream—I know him now,' thought Huldbrand to himself.
But Bertalda seemed to see nothing unusual about the stranger. She thought he was the Master of the fountain, and turning to Undine she asked her what the man had said to make her laugh so gaily.
'The day after to-morrow is your birthday, dear Bertalda,' said Undine. 'Wait only until then, and I will tell you the reason of my joy.'