In the Romantic period there was hardly a composer who was not influenced by the waltz. Chopin wrote about 15 piano waltzes, some of them are very fast, some are slower and more melancholy (sad). Brahms wrote 16 waltzes for piano duet. Many composers wrote waltzes in their operas, especially when the story is about people dancing at a party. The waltz was used a lot in operettas and ballets. Tchaikovsky wrote lots of waltz music in "Swan Lake", "Sleeping Beauty" and "The Nutcracker". Even Wagner, whose music is mostly very serious, wrote a waltz in his opera "Parsifal ". The rhythm of the waltz can be heard in a lot of orchestral music, e.g. Berlioz’s "Symphonie Fantastique". The great composers Anton Bruckner and Gustav Mahler preferred to use the old German Ländler in their symphonies.