The music, though labelled as an overture, is intended to stand as a complete work. Although programme music, it does not tell a specific story and is not "about" anything; instead, the piece depicts a mood and "sets a scene", making it an early example of such musical tone poems. The overture consists of two primary themes; the opening notes of the overture state the theme Mendelssohn wrote while visiting the cave, and is played initially by the violas, cellos, and bassoons. This lyrical theme, suggestive of the power and stunning beauty of the cave, is intended to develop feelings of loneliness and solitude. The second theme, meanwhile, depicts movement at sea and "rolling waves".