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.
Liebeslieder Walzer (ballet) Liebeslieder Walzer is a ballet by New York City Ballet co-founder and ballet master George Balanchine, based on the Brahms' "Liebeslieder Walzer", Op. 52, and their sequel "Neue Liebeslieder", Op. 65.