Weise's school plays. Kuhnau's theoretical treatise Fundamenta compositionis survives in a single manuscript which also contains an anonymous treatise on double counterpoint (Kurtze doch deutliche Reguln von den doppelten Contrapuncten) and two texts by Christoph Bernhard; the entire manuscript was at one point attributed to Johann Sebastian Bach. Unfortunately, Fundamenta appears to be a bad and partial copy from Kuhnau's original. The last five chapters are a direct copy from another Bernhard treatise on invertible counterpoint, while the discussion of modes is very similar to that in Walther's Praecepta der musicalischen Composition (1708), yet omits several passages included in Walther. The similarity raised an important question about Walther's well-known and highly regarded treatise: how heavily was it based upon Kuhnau's lost original? Or did both Walther and Kuhnau borrow from another writer, currently unknown? Kuhnau authored at least two more theoretical works, but those are only known by name: Tractatus de tetrachordo seu musica antiqua ac hodierna and De triade harmonica. His views on musical modes, solmization, and other matters are preserved in a letter dated 8 December 1717, published by Mattheson in Critica musica in 1725. In addition, the "Biblical Sonatas" include a large preface in which Kuhnau explores the idea of program music and various related matters. Family Kuhnau's nephew Johann Andreas Kuhnau, born in Annaberg on 1 December 1703, was one of the principal copyists for J. S. Bach. He attended the Thomasschule from 1718, and studied at the Leipzig University from 1719. He died after 1745. List of works Numerous works by Kuhnau are lost, including stage works, cantatas, numerous pieces of occasional music, and so on. Some cantatas, arias, and odes survive in text-only versions. Lost also were at least two treatises: Tractatus de tetrachordo seu musica antiqua ac hodierna and De triade harmonica. The following list only includes works that are extant in complete form. Keyboard Neuer Clavier-Übung, erster Theil, 7 suites (1689) Neuer Clavier-Übung, anderer Theil, 7 suites and 1 sonata (1692) Frische Clavier Früchte, 7 sonatas (1696) Musicalische Vorstellung einiger biblischer Historien, 6 sonatas (1700) Prelude in G major, organ Praeludium alla breve, organ Fugue in G major, organ Toccata in A major, organ Sacred vocal Ach Herr, wie sind meiner Feinde so viel Bone Jesu, chare Jesu Christ lag in Todesbanden Daran erkennen wir, dass wir in ihm verbleiben Das Alte ist vergangen Ende gut und alles gut Erschrick mein Hertz