Escher's print refers to a musical composition,The Drowned Cathedral by Claude Debussy (1862-1918). Composed in 1909, this piece for piano was inspired by an ancient Breton tale.
According to the legend, the city of Ys and its great cathedral, said to have lain in Brittany's Baie des Trépassés (bay of the dead), were swallowed up by the sea in the fourth or fifth century as punishment for the many sins of its inhabitants. Years later, so the story goes, the cathedral emerged unharmed at sunrise. But only to sink beneath the waters once again as night fell, while the fisherman looked on helplessly.