revered past masters....Mendelssohn did not regard the piano as a preferred medium for his most significant artistic statements". Mendelssohn's Songs Without Words (Lieder ohne Worte), eight cycles each containing six lyric pieces (two published posthumously), remain his most famous solo piano compositions. They became standard parlour recital items even during the composer's lifetime, and their overwhelming popularity, according to Todd, has itself caused many critics to underrate their musical value. As example, Charles Rosen equivocally commented, despite noting "how much beautiful music they contain", that "[i]t is not true that they are insipid, but they might as well be." During the 19th century, composers who were inspired to produce similar pieces of their own included Charles-Valentin Alkan (his five sets of Chants, each ending with a barcarolle) and Anton Rubinstein. Other notable piano works by Mendelssohn include his Variations sérieuses, Op. 54 (1841), the Rondo Capriccioso, the set of six Preludes and Fugues, Op. 35 (written between 1832 and 1837), and the Seven Characteristic Pieces, Op. 7 (1827). Organ music Mendelssohn played and composed for organ from the age of 11 until his death. His primary organ works are the Three Preludes and Fugues, Op. 37 (1837), and the Six Sonatas, Op. 65 (1845), of which Eric Werner wrote "next to Bach's works, Mendelssohn's Organ Sonatas belong to the required repertory of all organists". Opera Mendelssohn wrote some Singspiele for family performance in his youth. His opera Die beiden Neffen (The Two Nephews) was rehearsed for him on his 15th birthday. 1829 saw Die Heimkehr aus der Fremde (Son and Stranger or Return of the Roamer), a comedy of mistaken identity written in honour of his parents' silver anniversary and unpublished during his lifetime. In 1825 he wrote a more sophisticated work, Die Hochzeit des Camacho (Camacho's Wedding), based on an episode in Don Quixote, for public consumption. It was produced in Berlin in 1827, but coolly received. Mendelssohn left the theatre before the conclusion of the first performance, and subsequent performances were cancelled. Although he never abandoned the idea of composing a full opera, and considered many subjects – including that of the Nibelung saga later adapted by Wagner, about which he corresponded with his sister Fanny – he never wrote more than a few pages of sketches for any project. In Mendelssohn's last years the opera manager Benjamin Lumley tried to contract him to write an opera from