The Sunken Cathedral
This prelude is an example of Debussy's musical impressionism in that it is a musical depiction of, or allusion to, an image or idea. Debussy quite often named his pieces with the exact image that he was composing about, like La Mer, Des pas sur la neige, or Jardins sous la pluie. This piece is based on an ancient Breton myth in which a cathedral, submerged underwater off the coast of the Island of Ys, rises up from the sea on clear mornings when the water is transparent. Sounds can be heard of priests chanting, bells chiming, and the organ playing, from across the sea. Accordingly, Debussy uses certain harmonies to allude to the plot of the legend, in the style of musical symbolism.