Steve Shwartz:

>I don't know when the term came into use or why.  However, let me quote the
>opening sentence of a favorite book, Donald Clarke's The Rise and Fall of
>Popular Music: "In the beginning, there were two kinds of music: sacred
>and secular."
>
>Up until roughly the 19th century, nobody divided music into popular and
>classical.  If Josquin wrote masses, he also wrote frottolas.

As a historical aside I'd like to inject into the discussion the reminder
that the Church was very fearful of allowing popular influences into the
music.  But composers continued to blend genres and the congregation seemed
to appreciate it.  Thus there were "parody" Masses which were not parodies
but, rather, Masses that used a popular song as their melodic basis.  There
were also examples of the same music being used for both liturgical and
popular purposes, though I can't come up with any examples right now.

Ed