Operetta is a lighter form of opera with spoken dialogue, comic plots, and accessible melodies — the immediate ancestor of the musical.
Operetta emerged in mid-19th-century Paris with Jacques Offenbach, whose 'Orphée aux enfers' (1858) and 'La Belle Hélène' (1864) skewered classical mythology and Second Empire pretensions with irresistible tunes. Vienna took up the form: Johann Strauss II's 'Die Fledermaus' (1874) and 'Der Zigeunerbaron' (1885) created a confection of waltzes and witty intrigue that defined the Habsburg twilight. Franz Lehár's 'Die lustige Witwe' (The Merry Widow, 1905) became one of the most performed stage works of the early 20th century. In England, Gilbert and Sullivan's collaborations — 'H.M.S. Pinafore' (1878), 'The Mikado' (1885), 'The Pirates of Penzance' (1879) — produced a distinct English variant, savage in social satire and pristine in craft. Operetta seeded the American musical of Kern, Rodgers, and Sondheim. Lighter than opera, more melodically generous than the spoken play, it remains the most companionable form on the lyric stage.