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.
Die Schweizer Familie Die Schweizer Familie ("The Swiss Family") is an opera by the Austrian composer Joseph Weigl. It takes the form of a "Singspiel" in three acts. The libretto, by Ignaz Franz Castelli, is based on the vaudeville "Pauvre Jacques" (1807) by Charles-Augustin de Basson-Pierre and René de Chazet. The opera was first performed at the Theater am Kärntnertor in Vienna on 14 March 1809 and was a great success in German-speaking countries in the early 19th century.