Music historians usually judge 19th century's music for ballet to be of little importance. Therefore its compositional history is still virtually unexplored. Nevertheless - so the thesis of this essay - the ballet d'action seems to have close connections to one of the central genres of this time, program music. The mutual relationship of both types of music will be examined by means of two exemplary works - Ferdinand Herold's Lo Somnambule (1827) und Hector Berlioz' Symphonie fantastique (1830).