Ys

Ys, also known as Kêr-Is in Breton or Ville d'Ys in French, is a mythical city off the coast of Brittany, said to have been swallowed by the ocean. Most tales place it in the Baie de Douarnenez.

The legend centers on King Gradlon, who ruled Ys, a magnificent city built on land reclaimed from the sea. Described as a hub of commerce and art, Ys boasted a palace of marble, cedar, and gold. In some versions, Gradlon constructed the city at the behest of his daughter, Dahut, who adored the sea. To shield Ys from flooding, a dike with a single gate was built, opened for ships at low tide. The gate’s key, made of silver or gold, was kept by the king.

Gradlon is typically portrayed as pious, while Dahut, also called Ahez, is depicted as wayward, frivolous, or even a sorceress. In one ancient ballad, however, the people blame Gradlon for lavish excesses. The catastrophe unfolds when Dahut acquires the key, often stealing it from her sleeping father, either to admit a lover for a banquet or swayed by his flattery. In a wine-fueled error or mistaking the dike’s gate for the city’s, she opens it, flooding Ys.

As the sea engulfs the city, a saint—either St. Gwénnolé or St. Corentin—awakens Gradlon, urging him to flee. He escapes on horseback, initially with Dahut. As the waters close in, a voice commands him to cast off the “demon” he carries. In some versions, Gradlon himself throws Dahut into the sea on St. Gwénnolé’s orders. She drowns, but some tales claim she transforms into a morgen or mermaid, haunting the sea, combing her golden hair, and singing mournful songs.

In one account, St. Gwénnolé warns Gradlon of Ys’s debauchery and vanity, foretelling divine punishment. When a storm floods the city, Gradlon escapes to Quimper, as Dahut’s theft of the royal key triggers the disaster. Folk beliefs from the 19th century suggest that Ys’s ruins or the sound of its carillon can be glimpsed or heard at low tide.

Some versions claim Ys was founded over 2,000 years before Gradlon in a then-dry coastal area. By his reign, the encroaching sea submerged Ys at high tide, setting the stage for its legendary demise. The tale of Ys endures as a haunting blend of myth, morality, and the untamed sea.