Roughly around 1970, interest in the subject of Formenlehre decreased significantly, a trend that went hand in hand with a notable rediscovery of important eighteenth-century sources, in particular composition treatises by Joseph Riepel and Heinrich Christoph Koch. 2 Compared to the extensive and profound treatment Formenlehre received in the first half of the twentieth century as well as in the first postwar decades, after that critical moment very few textbooks, treatises, or studies on musical form were published in either German-or English-speaking countries. 3 Symptomatic of this tendency is Clemens 1 I would like to thank (in alphabetical order) Pieter Bergé, Poundie Burstein, Felix Diergarten, David Lodewyckx, and Christoph Wald for their critical readings of earlier drafts of this paper, as well as Claire Blacher for her help with language editing. The research presented here has been supported by the Research Foundation Flanders (FWO). 2 Riepel 1996 and Koch 2007. Important studies from the 1970s and 80s on the historical sources of form theory are cited in the editor's introduction to Koch's Versuch, see Koch 2007, 12 f.