The dominant form of opera in the 18th century was the Italian "opera seria," or serious opera. This operatic style emerged in the late 17th century in Naples, with Alessandro Scarlatti as the major composer. The opera seria placed emphasis on the solo voice and minimized the role of the chorus and orchestra. The vocal style of the period was known as "bel canto," which prized the high soprano voices of woman and male "castrati," or eunuchs. Themes in opera seria were serious, as its name implies, and the music was difficult to perform.
Singspiel had its roots in comic opera -- the Italian "opera buffa," the French "opera-comique" and the English ballad opera. Singspiel was always performed in German, and many of the operas of the genre featured German folk songs and themes taken from popular literature. Singspiel also made use of regular dialog to link together the various musical numbers, in contrast to opera seria, which used recitative to connect arias, choruses and ensembles. For most of the 18th century, singspiel was considered a lighthearted, lowbrow entertainment with simple music that actors without extensive musical training could perform.
Two early composers of singspiel were Christian Felix Weisse and J.C. Standfuss. Weisse translated the texts from several English ballad operas into German, and Standfuss set them to music. Later composers of singspiel opera include Johann Adam Hiller, Jiri Antonin Benda and Karl Ditters von Dittersdorf. As a group, these composers seemed to react against the seriousness and artificial conventions of opera seria by giving audiences a very different experience -- musical comedy. Hiller, who completed 12 singspiel operas, was the most popular composer of the genre.
While singspiel began as a reaction against the dominant opera form of its day, it eventually attracted composers like Mozart and Beethoven, who helped legitimize the genre and pave the way for Richard Wagner's Romantic German opera of the 19th century. Mozart's "Magic Flute" is considered singspiel because of its use of folk-song-like melodies, spoken dialog and comic characters, although the composer himself referred to the piece as "grand opera." Some critics consider Beethoven's "Fidelio" to be the very best example of the singspiel genre.