In what century was the the style of voices popular that the Liebeslieder Walzer, Op. 52 was in?
Ländler The Ländler (] ) is a folk dance in  time which was popular in Austria, south Germany, German Switzerland, and Slovenia at the end of the 18th century.
The Glow-Worm "Das Glühwürmchen", known in English as "The Glow-Worm", is a song from Paul Lincke's 1902 operetta "Lysistrata", with German lyrics by Heinz Bolten-Backers. In the operetta, it is performed as a trio with three female solo voices singing alternately and the women's chorus joining in the refrain. Rhythmically, it is in the form of a gavotte. The song, with its familiar chorus, was translated into English and became an American popular song.