Symphony No. 7 by Gustav Mahler was written in 1904–05, with repeated revisions to the scoring. It is sometimes referred to by the title Song of the Night, which Mahler never knew. Although the symphony is often described as being in the key of E minor, its tonal scheme is more complicated. The symphony's first movement moves from B minor (introduction) to E minor, and the work ends with a rondo finale in C major. Thus, as Dika Newlin has pointed out, "in this symphony Mahler returns to the ideal of 'progressive tonality' which he had abandoned in the Sixth". The complexity of the work's tonal scheme was analysed in terms of "interlocking structures" by Graham George.
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