JACQUES’ ANSWER: Yes, works by Johann Christoph Bach (Johann Sebastian’s uncle) — for instance “Ach daß ich Wassers gnug hätte,” a beautiful cantata for altus and strings — and Johann Ludwig Bach (Johann Sebastian’s cousin) are still performed. Johann Sebastian performed a large number of Johann Ludwig’s cantatas during the 1726–1727 season when he, after having completed several “Jahrgänge,” could relax. A Jahrgang, or plural Jahrgänge, is a complete set of cantatas for the year, including every Sunday and all church holidays. Quite a taxing schedule, especially when one does years of them back to back.
Regarding the Johann Christoph Bach cantata, altus was not a typo: altus can be either a female alto or a male countertenor, who would sing in falsetto. Both would be in the same range. Certain countertenors can even sing soprano! In the baroque period, some churches forbade women from singing in the choir. Countertenors were able to cover the alto and soprano ranges.
Hear versions of Johann Christoph’s cantata by Chatham Baroque and Christopher Lowrey.