English in 1951 (Schubert Thematic Catalogue) and subsequently revised for a new edition in German in 1978 (Franz Schubert: Thematisches Verzeichnis seiner Werke in chronologischer Folge – Franz Schubert: Thematic Catalogue of his Works in Chronological Order). Numbering issues Confusion arose quite early over the numbering of Schubert's late symphonies. Schubert's last completed symphony, the Great C major , was assigned the numbers 7, 8, 9 and 10, depending on publication. Similarly the Unfinished has been indicated with the numbers 7, 8, and 9. The order usually followed for these late symphonies by English-language sources is: No. 7: E major, D 729 No. 8: B minor, D 759 Unfinished No. 9: C major, D 944 Great C major No. 10: D major, D 936A An even broader confusion arose over the numbering of the piano sonatas, with numbering systems ranging from 15 to 23 sonatas. Instruments Among pianos Schubert had access to were a Benignus Seidner piano (now displayed at the Schubert Geburtshaus in Vienna) and an Anton Walter & Sohn piano (today in the collection of the Vienna Kunsthistorisches Museum). Schubert was also familiar with instruments by Viennese piano builder Conrad Graf. Recognition A feeling of regret for the loss of potential masterpieces caused by Schubert's early death at age 31 was expressed in the epitaph on his large tombstone written by Grillparzer: "Here music has buried a treasure, but even fairer hopes." Some prominent musicians share a similar view, including the pianist Radu Lupu, who said: "[Schubert] is the composer for whom I am really most sorry that he died so young. ... Just before he died, when he wrote his beautiful two-cello String Quintet in C, he said very modestly that he was trying to learn a little more about counterpoint, and he was perfectly right. We'll never know in what direction he was going or would have gone." However, others have expressed disagreement with this early view. For instance, Robert Schumann said: "It is pointless to guess at what more [Schubert] might have achieved. He did enough; and let them be honoured who have striven and accomplished as he did", and the pianist András Schiff said that: "Schubert lived a very short life, but it was a very concentrated life. In 31 years, he lived more than other people would live in 100 years, and it is needless to speculate what could he have written had