J. S. BACH Jonathan Berkahn - Victoria University - Victoria ...

The augmented-sixth is not a chord that occurs even amid the harmonic
splendours of the G minor Fantasia BWV 542 or the Chromatic Fantasia and Fugue
BWV 903. A product essentially of the Classical period, 94 it sits oddly in the
prevailing diatonic context. This chord is the one unmistakable piece of internal
evidence to cast doubt upon the prelude’s authenticity, and so it is with no great
surprise that we recognise this same movement among Krebs’s collected works.
The Prelude in C is not the only work of Krebs distinguishable from the style of
his teacher by a single chord. His chorale prelude O Ewigkeit, du Donnerwort is
thoroughly Baroque in style and texture, with precisely the same exception (Ex.1.21);
his fugue in C minor (Weinberger ed., vol.II, p.56) has the briefest augmented-sixth
chord, with a different, equally fleeting oddity a few bars later (Ex.1.22).
94 Although it had its origin with Paschal de L’Estocart as early as 1582, the augmented-sixth chord
was largely neglected until late in the eighteenth century.
95