Beethoven's String Quintet, Op. 29, has been described as a ‘wallflower’ work that, without enough suitors, remains on the sidelines of the string chamber music repertoire. But in the nineteenth century it had a prominent champion, Joseph Joachim, whose performances of the quintet must have attracted the attention of his close friend, Johannes Brahms. The opening theme of Brahms's String Sextet, Op. 18, is clearly reminiscent of the beginning of Beethoven's quintet. Evidence from Donald Francis Tovey's recollections of Joachim, Joachim's correspondence with the Brahms biographer Max Kalbeck, and the manuscript of Op. 18 shows that Joachim influenced an important revision that aligns the beginning of Brahms's sextet closely with the opening of Beethoven's Op. 29 also in terms of texture and formal design.
The striking tremolo opening and virtuosic scale passages in the finale of Beethoven's quintet prefigure similar elements in the last movement of Brahms's Op. 36 sextet. But the deeper relationship between these movements lies in certain shared formal elements: a common emphasis on sound, texture and sharp contrasts between agitato and pastoral elements as defining features of the overall form – and several distinctive similarities of contrapuntal strategy, form and tonal design between the substantial fugatos that dominate the development sections of both movements.
It is often observed that Brahms wrote chamber works in pairs. Scholars have often posited that his two string sextets form such a pair, but the separation of four years in their inceptions and his extensive use of Baroque-style materials composed in the 1850s in the later sextet have made this argument tenuous. It now emerges that an unusual pairing feature of Brahms's string sextets is that both works respond to Beethoven's ‘wallflower’ masterpiece.