The diffusion of music to the lower classes would not happen until the Industrial Revolution, some three centuries later. The reasoning for this is quite simple: as we all know, pre-industrial production of music is actually quite an arduous task, requiring an intense process of grinding its natural components (sourced from many locales across the old world) into a kind of powder, which is then blanched, molded into bricks, and added directly to the backgrounds from which the music receives its name.

Ultimately, background music would remain something of a luxury even for the middle class until the invention of color in the 1930's, as without color-coding, determining which notes would go where was a task only artisan craftsmen were equipped to perform.

The primary source for this post was Rush's "The Spirit of Radio: Greatest Hits 1974–1987", specifically that part where there's a bunch of long, spacey tracks that ultimately go nowhere.

I don't know much about the rest of Italy, but I am an expert in Florentine background music from 1300-1700. BGM was quite prolific throughout Florence during this time. Generally, only the nobility and the wealthy could afford to have their own personal theme music. Those without the money to afford theme music could still enjoy location-based music whenever there were at least three Italians within sight of each other (though often music wouldnt play in the counrtyside until there were at least five people present)

During which alternative timeline of the Borgias are you referring to? I believe there are serious disputes of whether the rules of background music fell under the rules of love or the rules of war in the version my future reality exists.

Interesting sidenote, Rodrigo Borgia was formerly a high ranking police official in Baltimore Maryland.