Not surprisingly, many of the excerpts from solos, duets, trios and concertos, and perhaps all of the anonymous exercises in the Solfeggi are by Quantz himself.
The fact that most of the duet excerpts are drawn from the Second livre de duo, published in Paris by the flautist and composer Michel Blavet in 1752, and from the Sei duetti, the only source for which is a manuscript copied around 1740, may be taken as evidence that much of the Solfeggi was compiled no earlier than the 1740S and 1750S.
If this hypothesis is correct, the Solfeggi provides the only known source for these lost duets.
Among the trios excerpted in the Solfeggi are the Italianate Six sonates en trio dans le gout italien, published by Boivin in Paris between 1731 and 1733.
Hefling's principal theoretical evidence for French inegalite in Germany comes from Quantz's Versuch einer Anweisung die Flote traversiere zu spielen (Berlin, 1752) and Solfeggi
for flute (Berlin, [c.
Austrian singer and teacher Ferdinand Sieber (1822-1895) who composed almost 700 solfeggi
put it this way:
The second aim is to seize the opportunity to demonstrate important points concerning performance practice by referring to comments made by Quantz himself in a manuscript treatise preserved in a copy dating from the later eighteenth century, Solfeggi
pour la flute traversiere avec l'enseignement (modern edition by Winfried Michel and Hermien Teske [Winterthur: Amadeus, 1978]), which contains commentated extracts from the same sonatas (respectively, QV 2:15, QV 2:28, and QV 2:35, following the numbering of Horst Augsbach's Johann Joachim Quantz: Thematisch-systematisches Werkverzeichnis (QV) [Stuttgart: Carus-Verlag, 1997]).
was without doubt his most well known publication, having been published first in Italy in 1790, and the complete set of thirty-six was attached to his 1791 London edition of The Italian Method of Singing.