My knowledge of classical music is that of a regular listener to a local classical music radio station. I have two related questions that have not had authoritative answers so far. Maybe somebody here can help.
Many classical works are referred to by a title that includes a key signature. Examples are Bach's Mass in B and Magnificat in E-flat major. My questions: 1) Why are these works referred to in this way (with the key signature)? 2) Why did the composers choose these particular keys in which to write?
Answers so far have involved differentiating this work from others by the same composer, and possibly because some orchestral instruments are limited in the notes they can play, so wouldn't "work" in other keys. Nobody has been very sure of their answers.
Who can enlighten me?