Program music allowed many Romantic composers to meet the challenge of creating musical structures that were both compatible with Romanticism’s need for expressive individuality and, at the same, provided a source of compositional cohesion that audiences could understand and follow. One type of program music, the program symphony, is exemplified by Hector Berlioz’s Symphonie fantastique of 1830. The essence of this unique work is the idée fixe (“fixed idea”), which Berlioz uses to provide abstract, structural coherence in this five-movement masterpiece.