The Knights of the Fish
The Knights of the Fish is a Spanish fairy tale collected by Fernan Caballaro in Cuentos. Oraciones y Adivinas. Andrew Lang included it in The Brown Fairy Book. Another version of the tale appears in A Book of Enchantments and Curses by Ruth Manning-Sanders.
An industrious but poor cobbler tried to fish until he was so hungry that he thought he would hang himself if he caught nothing. He caught a beautiful fish. It told him to cook it and then give two pieces to his wife, and bury two more in the garden. He did this. His wife gave birth to twin boys, and two plants sprang up, bearing shields, in the garden.
When the boys were grown, they decided to travel. At a crossroad, they parted ways. One found a city grieving, because every year a maiden had to be offered up to a dragon, and this year the lot had fallen on the princess. He went to see where the princess was, and then left her to fetch a mirror. He told her to cover it with her veil and hide behind it; when the dragon approached, she was to tear the veil off. She did, and the dragon stared at his rival, identical to him. He threatened it until he finally smashed it to pieces, but as every fragment reflected him, he thought he too had been smashed. While it was still baffled, the knight killed it. The king married him to his daughter.
The princess showed him all over the castle, and he saw a castle of black marble, and was warned that whoever went to it never returned. He set out the next day. When he blew his horn and struck the gate, a woman finally opened the door. Echoes warned him off. He lifted his helmet, and the woman, who was an evil witch, let him in because he was so handsome. She told him that he would marry her, and he refused. The witch showed him over the castle and killed him by dropping him through a trapdoor.
His brother came to the city, and was taken for him. He kept quiet, so he could help his brother, and told the princess that he had to go back to the castle. He demanded to know what happened to his brother, and the echoes told him. When he met the witch, he quickly stabbed her with his sword, and then she asked him to save her life with magical plants from the garden. He found the bodies of his brother and all her other victims, whom he restored with that magic, and also a cave full of the maidens killed by the dragon, whom he also restored. After they all escaped, the witch died and her castle fell.