This ballade, like its two predecessors, is assumed to draw on the poetry of Chopin's friend Adam Mickiewicz (Chopin never confirmed the precise sources or programs connected with these works). Dedicated to Princess Pauline de Noailles, one of the composer's pupils, the piece is said to be inspired by Mickiewicz's "Undine." It's the tale of a water sprite who falls in love with a mortal; she cannot have him because her watery embrace would be fatal. (The sprite appears in another celebrated piano work, the first movement of Ravel's Gaspard de la nuit.)

Far less turbulent than the other ballades, this one begins almost coyly, with a rising yet hesitant phrase in moderate tempo that gives way to a slightly more emphatic theme, dominated by its gently rocking rhythm, suggesting the waves of Undine's natural habitat. This material rises in volume and intensity, but quickly recedes into splashes and gentle cascades of notes in the keyboard's upper reaches.

This aquatic idyll gives way to a new section, still dominated by the rocking rhythm but now arising from a simple, almost childlike tune. Within a few measures this melody grows more complex and the music heaves with passion without becoming truly turbulent. The music ebbs, making way for a return of the section's opening material. Now more gradually, the tempo and filigree increase and recede again. The ballade's opening theme returns without overtly marking a new section; it's incorporated into the tempo and texture the music has already established, and propels a long, restless passage that builds to the most intense climax of all -- yet one that suggests frustrated, passionate love rather than the high tragedy of the other ballades.