Musical theater
Around 1850, the French composer Hervé was experimenting with a form of comic musical theatre that came to be called opérette.  The best known composers of operetta were Jacques Offenbach from the 1850s to the 1870s and Johann Strauss II in the 1870s and 1880s.  Offenbach's melodies, and his librettists' satire, formed a model for the musical theatre that followed.