Although he set many poems by Goethe and two by Schiller, Brahms showed a predilection for the work of second-rate poets. Brahms tended to choose texts for their musical potential; however, periods of increased song output in his life seem to coincide with the presence of a woman. For instance, the fifteen songs Brahms composed in 1858 revolve around his relationship with Agathe von Siebold, a singer in Göttingen for whom he composed the Lieder, Opp. 14 and 19 and the Duets, Op. 20. Twenty-one of Brahms' 196 solo songs are from 1877, the year Brahms was "re-acquainted" with Elisabeth von Herzogenberg (née Stockhausen).
Brahms once wrote to Clara Schumann that the folksong is the ideal toward which the composer of songs must strive. With the release of the Nine Songs, Op. 69, Brahms would distance himself from the language of the folksong. In the Duets, Op. 20, however, folksong aspects are clearly evident in the diatonic melodies, repetition of the last words of a verse, consistent rhythmic patterns and the lack of lengthy piano introductions. The Duets, Op. 20, are for soprano and alto voices with piano accompaniment. They were published in 1861 and first performed on January 29, 1878, in Vienna.
"Weg der Liebe" (The Way of Love) Part I, is from Herder's Stimmen der Völker, composed in 1858. The poem tells us that love will find a way, because there is no mountain high enough, no valley low enough to prevent it. Even when the Phoenix fails to rise, love will still find a way. Brahms chose an overall ABA' format in E major and 6/8 meter. The soprano and alto parts maintain the same rhythm through nearly the entire A section, the soprano part having slightly more shape. The central section, itself a rounded structure, is set off not so much by harmony as by texture, for it begins canonically. In the middle of section B the writing again becomes homorhythmic and modulates to C major, anticipating the key of "Weg der Liebe," Part II. Thus, when the canonic music returns, it is a third lower. A reprise of the entire first section, with some modification, closes the duet.
"Weg der Liebe" Part II is also from Herder's Stimmen der Völker, and was composed in 1858. The text likens love to the Gordian Knot--what is the point of breaking it? Again there is crossing of mountains and oceans, which Brahms sets in C major and again in 6/8 meter, but to a much slower tempo than in Part I. The three verses are set strophically, moving astray harmonically as far as D flat major near the end of the verse.
Composed in 1860, "Die Meere" (The Sea) is from a traditional Italian folksong. A lover's restless heart contrasts with the still sea in this nocturnal rumination on love. Brahms' primary modification in this varied strophic setting is at the end of the verse, where a repetition of the final line leads to E major. Although the end of the voice part closes on E major, the piano passage returns to E minor.