In opera, there was a tendency for the forms usual in classical and baroque opera to be loosened, broken, and merged into each other. This reached its climax in Wagner, where arias, choruses, recitatives and ensemble pieces cannot easily be distinguished from each other. Instead there is a continuous flow of music.
Other changes occurred as well. The decline of castrati led to tenors being given the heroic lead in operas as a rule, and the chorus took on a more important role. Towards the end of the Romantic period, verismo opera, depicting realistic, rather than historical or mythological, subjects became popular in Italy. France followed with operas such as Bizet's Carmen.
Examples of extra-musical inspiration include Liszt's Faust and Dante symphonies and his symphonic poems, the Manfred Symphony by Tchaikovsky, Mahler's First Symphony based on the novel Titan and Saens Sans suite Animals Suite, from which the very popular "The Swan" is drawn. Composers such as Schubert would use song melodies in their extended works, and other composers such as Liszt, would transcribe opera arias and songs into purely instrumental works.









