Progressive tonality

Progressive tonality is the music compositional practice whereby a piece of music does not finish in the key in which it began, but instead 'progresses' to an ending in a different key or tonality. To avoid misunderstanding, it should be stressed that in this connection 'different key' means a different tonic, rather than merely a change to a different mode (see: Picardy third and List of major/minor compositions): Gustav Mahler's Second Symphony (1888–94), for example, which moves from a C minor start to an E-flat major conclusion, exhibits 'progressive tonality'—whereas Ludwig van Beethoven's Fifth Symphony (1804–08), which begins in C minor and ends in C major, does not. A work which ends in the key in which it began may be described as exhibiting 'concentric tonality'. The terms 'progressive' and 'concentric' were both introduced into musicology by Dika Newlin in her book Bruckner, Mahler, Schoenberg (1947).

In instrumental and orchestral music, progressive tonality is a development of the later nineteenth century, but its seeds are already evident in the early part of the century. One of the results of Franz Schubert's creation of the four-movement fantasy (in such works as the Wanderer Fantasy and the Fantasy in F minor) was that individual movements no longer ended in the key in which they began, but rather in the key of the immediately following movement. Other composers became increasingly fascinated with ending movements in unstable ways. Fanny Hensel, Robert Schumann, and Frédéric Chopin all employed, at one point or another, the technique of avoiding a full cadence on the tonic in the last measure of a piece to create a sense of ambiguous closure (examples of this are: Hensel's lied 'Verlust,' published by Felix Mendelssohn as Op. 9, No. 10; Schumann's lied 'Im wunderschönen Monat Mai' from Dichterliebe, Op. 48, No. 1; Chopin's Mazurka in A minor, Op. 17, No. 4). Chopin explored progressive tonality in his instrumental music as well (see his second ballade), and efforts by him and other progressive composers such as Hector Berlioz and Franz Liszt (whose 1855 Dante Symphony begins in D minor and ends in B major), had a profound effect on later composers, such as Richard Wagner, whose harmonic developments in Tristan und Isolde and Der Ring des Nibelungen were altogether different from the use of tonal language by previous composers. Charles-Valentin Alkan also contributed several pieces, such as his Grande sonate 'Les quatre âges' (beginning in D major and ending in G-sharp minor), his Symphony for Solo Piano (beginning in C minor and ending in E-flat minor), and his Concerto for Solo Piano (beginning in G-sharp minor and ending in F-sharp major). Progressive tonality in the late nineteenth century no doubt reflects the increasingly programmatic and narrative orientation of 'late Romantic' music. Thus it occurs in five of the symphonies of Mahler, but never at all in the symphonies of his predecessors Brahms or Bruckner. As Mahler's 7th Symphony shows, 'progressive tonality' may occur within an individual movement (the work's first movement 'progresses' from an implied B minor to an explicit E major) as well as across an entire multi-movement design (the symphony ends with a C major finale).

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