I examine how to create Classical Music here. I embedded a Classical Music Composing function into the Automated Composing System. I mention how I developed these functions on this page.
Classical music uses chords differently than popular music.
At least, the chord symbols are not displayed in the music scores. However, Classical music uses chords, of course. I think that Classical music allocates one chord to each melody note. Classical music has more restrictions than popular music, and it is very picky about dissonance. So, this idea is also included in the Automated Composing System.