'Back in the day' - late 50's into '62, the accordion studio I studied/worked at had an accordion orchestra that played Classical music - 1812 Overture, Beethoven's 5th, Mussorgsky, Rossini, etc., etc., ... all the horn/woodwind parts had to be transposed from 'Eb/Bb' parts to 'C' for the accordion ... that was one of my jobs ...