N ° 10 of the first book of Preludes (HN 383) of 1910, this separate edition shows a Debussy with an overflowing imagination, evoking the ancient city of Ys, engulfed by the sea. Debussy willingly played this work himself and even engraved a recording on rolls. This recording is very revealing of its tempo options. The indication Prélude, we obviously think of Chopin, clearly refers to traditional forms, to which the now famous composer turned little by little again. As with all Préludes, the title of the work is only mentioned at the end of the piece, so its program is just sketched in passing.