The Submerged City French folktale

Who has not heard of the submerged bells of Ys, and who has not heard them ring?

In the early days the city of Ys was ruled by a prince called Gradlon the Great. Gradlon was a prudent prince, and defended his capital of Ys from the invasions of the sea by constructing an immense basin to receive the overflow of the water at high tide. This basin had a secret gate. The king alone had the key to open and close it with at the necessary times.

Gradlon had a wayward child, the princess Dahut. Once while her father was sleeping, she gave a secret banquet to her lover. Drunk, the pair decided to open the sluice-gate. The princess stole noiselessly into her sleeping father's chamber. There she took the guarded key from his girdle and opened the gate. The water at once rushed in and began to submerge the city.

King Gradlon was awakened somehow, and tried to flee as the torrent was reaching the palace. He mounted his horse, set his witless daughter behind him, and set off at a gallop. The incoming flood seethed and boiled, and the torrent was about to overtake and submerge him when a voice called out: "Throw your witless daughter into the sea, if you will not perish."

At that moment the princess fell from the horse's back into the water and became a mermaid, and the torrent at once stopped. Gradlon managed to escape, safe and sound, but he no more could enjoy the sight of his daughter combing her golden hair in the midday sun, and he had lost is capital and the wealth he had gathered there too.

From time to time afterwards fishermen told of meetings with a golden-haired white daughter of the sea. They could sing her songs too. They were as plaintive and furtive as the sound of waves.