Beschreibung:
The fact that there are so few authentic documents regarding the allocation of forces in Bach’s concerted performances makes it impossible to accept absolute statements about his practices. Among the most important sources of information are the records of the Thomasschule in Leipzig. In a document of 1730, Bach explains that a cantata choir must consist of at least 12 (or, better yet, 16) singers—that is, 4 soloists and 8 ripienists. These numbers are given credence by, among other sources, a list of choir members in 1744–5. In addition to the pupils whose names are documented in such lists, Bach had access to alumni, his sons and private students, apprentices of the Leipzig town pipers, as well as day students. Unfortunately the involvement of these additional forces is difficult to assess because their participation is rarely recorded in official documents. According to the rector of the Thomasschule, Johann Mathias Gesner, Bach directed '30 or 40 musicians' (singers and instrumentalists). The documentary evidence, however, is too limited to draw unambiguous conclusions about how these musicians were used.