Group V Manuscripts
The surviving sets of MSS from Vienna provenance are part of invaluable documentary evidence in the form of music, portraying Mozart's admiration for Bach's fugues. Since Warren Kirkendale discussed this remote branch of L in 1960s in the context of Mozart's KV 405, a number of new sources have come to light. More recent study serves to show that there are two main branches Stockholm and Q10782, both of which originate from the lost source V' that van Swieten brought from Berlin. The major difference between them, namely that the former consists of one prelude and 16 fugues, some of which are transposed, and the latter contains all the 24 fugues in the original key, can be considered as the difference in philosophy behind collections compiled from the same origin. They also diverge in other minor aspects (e.g., notational policies and other unique variants), but this cannot invalidate the central hypothesis that they originated in a manuscript in Berlin.
Interestingly, both sources contain revisions in several layers. Closer examination reveals that some of the revised readings are the result of detailed comparison between the sources themselves. The study of handwriting indicates that the scribe of Stockholm, J. G. Albrechtsberger, entered revisions in Q 10782, often identical to those he made in Stockholm.
Yet a perhaps more discernible characteristic of V is the fact that it contains numerous textual errors of various kinds, as well as presenting unique, often surprisingly competent, variant readings. Such departures are particularly numerous in the sub-group of Q 10782 (referred to as Vii): this may be related to the fact that the notational convention of Vii, i.e., the use of accidentals and the use of US / LS, is systematically overhauled. Close inspection of Q 10782 reveals that many more corrections were made at the copying stage. From this point of view, it is possible to state that V'' was a poorly presented copy, and that it had already contained some of the unique variant readings. Further study of these variants suggests that these unique readings are a part of conjectural revision activity presumably carried out in V', where voice-texture is reduced. A similar nature of revisions is also found in both Stockholm and Q 10782, which sometimes results in different readings. It can be concluded that the two branches from V' appear to have been revised freely, partly by Albrechtsberger, introducing many unique variant readings, while correcting some obvious errors.
The source V''' stemmed from a late stage of revision in Q 10782: while it contains most of the unique readings, it corrects some notational aspects and at the same time, introduces new errors / variants as a result of copying error. This MS was thus made by a scribe whose task was to make a better, more readable musical text than that of Q10782. Two MSS are known to have survived: Berea and Q 11731. Federhofer (title page and the first page of Fg.C) can be considered as part of V'''. The other leaf of Federhofer, containing Fg.B (transposed to C major), also stems from the branch of Vii.