Classical music is another huge genre, but most people think of the piano or symphony orchestra driven chamber music written by people such as Bach, Beethoven, and other big names. It usually either gets used to indicate something as being before the 20th century in either setting or tone. Often gets used to show a character as being either not with the times or otherwise old fashioned to the point of stodginess. If your story features criminals, expect to see it indicating stuff related to the Italian Mafia. Examples: