Dumage (1707) and others. Bach's formulation of the title page follows some of these earlier works in describing the particular form of the compositions and appealing to "connoisseurs", his only departure from the title page of Clavier-Übung II. Although Clavier-Übung III is acknowledged to be not merely a miscellaneous collection of pieces, there has been no agreement on whether it forms a cycle or is just a set of closely related pieces. As with previous organ works of this type by composers such as François Couperin, Johann Caspar Kerll and Dieterich Buxtehude, it was in part a response to musical requirements in church services. Bach's references to Italian, French and German music place Clavier-Übung III directly in the tradition of the Tabulaturbuch, a similar but much earlier collection by Elias Ammerbach, one of Bach's predecessors at the Thomaskirche in Leipzig. Bach's complex musical style had been criticized by some of his contemporaries. The composer, organist and musicologist Johann Mattheson remarked in "Die kanonische Anatomie" (1722): Until 1731, apart from his celebrated ridiculing in 1725 of Bach's declamatory writing in the cantata Ich hatte viel Bekümmernis, BWV 21, Mattheson's commentary on Bach had been positive. In 1730, however, he heard by chance that Gottfried Benjamin Hancke had been commenting unfavourably on his own keyboard technique: "Bach will play Mattheson into a sack and out again." From 1731 onwards, his vanity pricked, Mattheson's writing became critical of Bach, whom he referred to as "der künstliche Bach". Over the same period Bach's former pupil Johann Adolf Scheibe had been making stinging criticisms of Bach: in 1737 he wrote that Bach "deprived his pieces of all that was natural by giving them a bombastic and confused character, and eclipsed their beauty by too much art." Scheibe and Mattheson were employing practically the same lines of attack on Bach; and indeed Mattheson involved himself directly in Scheibe's campaign against Bach. Bach did not comment directly at the time: his case was argued with some discreet prompting from Bach by Johann Abraham Birnbaum, professor of rhetoric at the University of Leipzig, a music lover and friend of Bach and Lorenz Christoph Mizler. In March 1738 Scheibe launched a further attack on Bach for his "not inconsiderable errors": In the advertisement in 1738 for his forthcoming treatise, Der vollkommene Capellmeister (1739), Mattheson included a letter by Scheibe, resulting from his exchanges with Birnbaum, in which Scheibe expressed