Ys was a magnificent coastal city protected by dikes, drowned when Dahut stole the key to the gates. It parallels other flood myths like Atlantis. In poetry, Ys evokes themes of divine punishment, feminine transgression, and submerged memory—often appearing in Celtic revivalist or Symbolist works as a haunting image of beauty destroyed by moral failure, its bells still ringing beneath the waves.

Ys (or Is) is a Breton legend of a city submerged off the coast of Brittany due to the sinfulness of its princess, Dahut, who stole the key to the sea gates. Only her father, King Gradlon, escaped. Like Atlantis or Lyonesse, Ys symbolizes divine punishment, female transgression, and the sea as moral judge. In poetry—especially Breton and French Symbolist verse—it evokes drowned memory, coastal melancholy, and the fragility of human order against elemental forces.