In 1827, Schubert wrote the song cycle Winterreise (D. 911), a colossal peak in art song ("remarkable" was the way it was described at the Schubertiades), the Fantasy in C major for violin and piano (D. 934, first published as op. post. 159), the Impromptus for piano, and the two piano trios (the first in B-flat major (D. 898), and the second in E-flat major, (D. 929); in 1828 the cantata Mirjams Siegesgesang (Victory Song of Miriam, D 942) on a text by Franz Grillparzer, the Mass in E-flat major (D. 950), the Tantum Ergo (D. 962) in the same key, the String Quintet in C major (D. 956), the second "Benedictus" to the Mass in C major (D. 452), the three final piano sonatas (D. 958, D. 959, and D. 960), and the song cycle 13 Lieder nach Gedichten von Rellstab und Heine for voice and piano, also known as Schwanengesang (Swan-song, D. 957). This collection, while not a true song cycle, retains a unity amongst the individual songs, touching depths of tragedy and of the morbidly supernatural, which had rarely been plumbed by any Composer in the century preceding it. Six of these are set to words by Heinrich Heine, whose Buch der Lieder appeared in the autumn. The Symphony in C major (D. 944) is dated 1828, but Schubert scholars believe that this symphony was largely written in 1825–1826 (being referred to while he was on holiday at Gastein in 1825—that work, once considered lost, is now generally seen as an early stage of his C major symphony) and was revised for prospective performance in 1828. This was a fairly unusual practice for Schubert, for whom publication, let alone performance, was rarely contemplated for most of his larger-scale works during his lifetime. The huge, Beethovenian work was declared "unplayable" by a Viennese orchestra. In the last weeks of his life, he began to Sketch three movements for a new Symphony in D major (D 936A).