ABSTRACT

Before discussing the second-act finale of Don Giovanni, it is important to understand the overall function of the tonal triangle that I have been saying plays such a seminal role in the opera: D-D minor-B@. This triangle of keys lies behind many of the large-scale structures, and also sounds as foreground chord sequences at dramatically significant moments.1 Thirds relations, like those of this triangle, were used increasingly by composers at the end of the eighteenth century. Haydn used thirds relations within and between movements of his Op. 76 quartets of 1797, and then again to structure the tonalities of set numbers in The Creation (1799) and The Seasons (1801). Beethoven used thirds relations extensively throughout his later work, and in a specifically thematic sense in both Fidelio (1804) and his ninth symphony (1824), which is suspended between the same harmonic triad as Don Giovanni. Così fan tutte uses a similar harmonic triangle of thirds relations – C-A minor-A major – though far less often than in Don Giovanni.