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

sonata movement sets up certain expectations for the recapitulation; there is a sense in
which the completion of an unfinished sonata movement is as much a business of
copying as composing. To be sure, twentieth-century analysts have made much of the
irregularity of actual Classical practice; but even in Haydn (who is normally much less
regular than Mozart) the amount of literal or near-literal repetition is large compared to
the Fortspinnung-generated forms of the previous generation. In Stadler’s completion
of the Allegro in B flat K.400/372a, where he needs to supply a recapitulation to an
existing exposition and development, all he has to do is tweak bb.10-11 of the
transition to the dominant, and the sonata will conclude itself perfectly satisfactorily.
In other cases Stadler had to supply more than a recapitulation with suitable
transpositions. The Larghetto and Allegro for two pianos in E flat (K.deest) was 108
bars, much of it only for one piano, before he expanded it to 226 bars. In the
violin/piano sonata movement K.403/385c, twenty bars of Mozart gave him the cue for
a 144-bar movement.
More enigmatic is the question of what Mozart had in mind with his ‘Fantasia’
in C minor K.396/385f. The autograph appears to be an unfinished sonata movement
for violin and clavier, perhaps one of the several that Mozart began writing for ‘ma
trés chére Epouse’ in 1782. But the violin writing is a long way from the sophisticated
interplay of Mozart’s mature sonatas, recalling the most primitive ‘accompanied
sonatas’ of the 1770s. It is silent for more than three-quarters of the exposition,
entering only in b.26 with a subsidiary alto part. Was the violin an afterthought? This
seems unlikely, given what we know about Mozart’s usual compositional procedure.
It is hard to see what the violin could have added to the rich texture of the first twenty-
five bars, and quite understandable why Stadler decided to present it to the public as a
piano piece (the few violin notes are easily incorporated into the texture). The title is
Stadler’s own; if indeed the original was intended to be one of Constanze’s violin
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