The belief widely accepted by scholars that the only three surviving manuscript sources of Hans Buchner's (1483–1538) Fundamentum (CH-Bu F I 8a, CH-Zz S 284a, CH-Zz S 284b) are "copies" of an "Urtext" is refuted by paleographic evidence as well as an analysis of the network of people who contributed to the sources. It turns out that the three elements of the Fundamentum —written text, tables of musical examples, and compositions—show a different degree of interference by the scribe. Because all three sources were written by the music teacher Christoph Piperinus, a study of other music manuscripts written by him sheds new light on Fundamentum. While its compositions seem to be "copies" in the modern sense, paleographic evidence strongly suggests that Piperinus has made a selection of a larger number of compositions and tables and not only revised but also wrote parts of the text anew. As a result, Fundamentum—in the form of CH-Bu F I 8a—is not a copy, but rather appears to be created as late as 1550. Watermarks from all the sources are attached.