Operas and operettas are basically plays (tragedies, dramas and comedies) set to music. Most feature solo voices and choruses and the whole is accompanied by orchestra. The operetta is a light music version of the opera form, but the French ‘Opéra Comique’ and the German ‘Singspiel’ also represent lighter forms of opera. The most frequently performed opera composers are Mozart, Rossini, Puccini and Verdi, while the most successful operetta composers are Johann Strauss II, Offenbach, Lehár and Sullivan.