Even more difficult problems are posed by early work,
BWV 566, which, like BWV 549, was probably composed by
the time of Bach's arrival at Weimar in 1708. The
numerous questions raised by this work can only be
touched upon here. BWV 566 exists in versions in C
major and E major. Although Bach probably drafted it in
E, the E major version survives only in late,
unreliable sources. Whether Bach himself carried out
the adaptation in C major has been questioned, but the
sources provide no basis for ...(+)
Even more difficult problems are posed by early work,
BWV 566, which, like BWV 549, was probably composed by
the time of Bach's arrival at Weimar in 1708. The
numerous questions raised by this work can only be
touched upon here. BWV 566 exists in versions in C
major and E major. Although Bach probably drafted it in
E, the E major version survives only in late,
unreliable sources. Whether Bach himself carried out
the adaptation in C major has been questioned, but the
sources provide no basis for doubting its authenticity.
Numerous variant readings in both versions, however,
indicate that the text underwent frequent emendation,
sometimes by copy¬ists, leaving the composer's
intentions uncertain at many points. The edition
presents the C major version first, as it probably
contains a number of Bach's later readings; a
reconstruction of the version in E follows.
The earliest printed edition of BWV 566, in E major,
appeared in 1867 in volume 15 of the old Bach
Gesamtausgabe under the title "Toccata III." Neither
version is des¬ignated a toccata in any of the sources
used for the present edition. But the varying headings
in the sources indicate some uncertainty as to the
proper title of the work, which comprises four
alternating preludial and fugal sections. The present
edition adopts the title Pradudium, by analogy to
similar works by Dieterich Buxtehude. The work was
probably composed in E for an instrument that had
either pedal c#' or C# but not both. This instrument
perhaps also lacked manual c3, for the highest note in
the E major version is b2. The C major version was
likely an adaptation to permit performance on an
instrument lacking pedal c#' (as well as C#), while
avoiding problems of temperament created by the use of
E major. The adaptation produced a work with an
unusually low tessitura, never rising above g2 (compare
BWV 531 in the same key, which uses all notes up to
c3). Nevertheless, the transmission of the C major
version through two associates of Bach strongly implies
that this version, like BWV 549 (in C minor), was at
least sanctioned by the composer. That Bach himself was
the arranger is likely in view of the fact that the C
major version was copied independently by his Weimar
pupil Krebs and later by his friend Kellner. (Source:
J.S.Bach Samtl. Orgelw. Band 1 (Breitkopf)