Des Knaben Wunderhorn
To promote his concept of the "Volk", he published letters and collected folk songs. These latter were published in 1773 as "Voices of the Peoples in Their Songs" ("Stimmen der Völker in ihren Liedern"). The poets Achim von Arnim and Clemens von Brentano later used "Stimmen der Völker" as samples for "The Boy's Magic Horn" ("Des Knaben Wunderhorn").