Gradlon the Great was a semi-legendary 5th century "king" of Cornouaille who became the hero of many Breton folk stories. The most famous of these legends is the story of the sunken city of Ys. He is supposed to have been the son of Conan Meriadoc, but Conan lived much earlier in the late 4th Century.
Statue of King Gradlon at Quimper Cathedral, by sculptors Amédée Ménard and Alphonse Le Brun (1858)
Lyrics and sheet music for the Breton gwerz "Ar Roue Gralon ha Kear Is" ("King Gradlon and the City of Ys", 1850)
Ys, also spelled Is or Kêr-Is in Breton, and Ville d'Ys in French, is a mythical city on the coast of Brittany that was swallowed up by the ocean. Most versions of the legend place the city in the Baie de Douarnenez.
Flight of King Gradlon, by E. V. Luminais, 1884 (Musée des Beaux-Arts, Quimper)
Lyrics and sheet music for the Breton gwerz "Ar Roue Gralon ha Kear Is" ("King Gradlon and the City of Ys", 1850). This uses the archaic spelling Kear Is for the city of Ys.
Stained glass window by Gabriel Léglise representing "Saint Guénolé, abbé de Landévennec, sauvant le roi Gradlon lors de la submersion de la ville d'Ys" Church of Saint-Germain Kerlaz.
Title page of the first edition of La Vie des saincts de la Bretaigne armorique by Albert Le Grand, 1636