Not much interest in this here :? , but in the "Herald" I received a few responses.
Thought I'd share them with the "Master" folks.
From Pierre in Norway:
Hello,
There are several minor works originally written for trumpet. One can classify them in 2 groups:
(i) Works written for "normal" natural trumpet, just based in a tonality other than the written C major playable by the instrument. For example, the Biber duets alluded to by NE are in written G minor, taking advantage of the available (though flat!) Bb in the C-based harmonic series: C-G-C-E-G-Bb-C-D-E-F/F#-G-A-Bb-B-C...
One of the Biber sonatas for 1 trp and strings is in G minor, played on C trp. As mentioned, there is/are a few Bach cantatas also. Check CD's by Crispian Steele-Perkins, he has recorded quite a lot of more obscure works on nat, with a few minor pieces as well.
(ii) Works originally written for slide trumpet, meaning nat trp but with retractable leadpipe, not soprano trombone or the later English slide trp written for by Brahms and popular in England until late 19th C. The only works I can think of right now are numerous Bach cantatas and the very famous Funeral for Queen Mary by Purcell (trp quartett).
Actually, if you check the Purcell Musica Rara edition, you will see a very strange piece, in usual D major with available notes for D nat, only that the ending has a spectacular and exposed written Eb (concert F). Maybe intended for slide-trp or bent out of proportion from E by very skilled player?
But the large majority of baroque era works with trp. (including B minor mass!) are in major keys, with the occasional minor relative modulation in the middle section, but where the trp. has less of a soloistic role.
Hope this helps and that other more knowledgeable chime/correct in!!
Pierre