French composer Hervé gets the credit for creating operetta. He penned L’Ours et le pacha in 1842, taking some of the conventions of opéra comique and marrying it with vaudeville.
But it was Jacques Offenbach’s elaborate, risqué works that really propelled operetta into the popular consciousness.
His music was infectious and his stories offered humour with bite (for example, Orpheus in the Underworld, 1858).
Best of all, his operettas were erotic and sometimes downright pornographic, performed by courtesans in Paris to theatres filled with men.
The giants of Viennese operetta took the form in a different direction. Johann Strauss wrote nostalgic, sentimental works, full of dance music and romance (think Die Fledermaus, 1874). Franz Lehár continued his legacy with The Merry Widow (1905). Emmerich Kálmán moved from Hungary to the hotspot of operetta, Vienna in the early twentieth century. He fused Viennese waltz with Hungarian folk dance.
Gilbert and Sullivan, flying the flag for English operetta, wrote fourteen comic operas, including H.M.S Pinafore (1878), The Pirates of Penzance (1879) and The Mikado (1885).
Victor Herbert was the most famous American operetta composer (Naughty Marietta, 1910, Sweethearts, 1913).