Manuscript Am. B. 340, owned by the Staatsbibliothek Berlin, contains three works that are generally believed to be composed by Wilhelm Karges: a Fantasia, a Prelude, and a Capriccio. The Capriccio is only half the work of Karges, as the second half of it is derived from a piece by Froberger. The reason these three works are accepted as works by Karges is that the scribe of the manuscript (Karges himself?) writes the initials "W.K." near the title of the piece. The rest of the manuscript contains pieces, for which either a composer is given by name, by initials or not at all. The pieces that are indicated to be composed by someone else than Karges are for the most part free adaptations of the original. The manuscript is therefore not a reliable source for those works. It gives however a fascinating glimpse into how works like these in the early Baroque period were adapted and transformed to suit the need of scribe of the manuscript. The very first work in the manuscript is a Fantasia, for which no composer is given. That raises the question whether it is an adaption of another existing work, or an original composition. Until now I have not been able to find an existing work on which this Fantasia could be based. In style it is very reminiscent of the Fantasia in the same manuscript that has the initials "W.K." below the title. It is therefore tempting to suppose this Fantasia was composed by Karges himself.
Score available here: http://partitura.org/index.php/wilhelm-karges-fantasia/