Now, all you need to know is what polyphony, organum, and motet are.
Actually, there is a bit of controversy surrounding Hildegard. Apparently, she's not famous because her compositions are spectacular; she's famous because she's a she. Some musicologists are suggesting that someone simply placed an authentic medieval nun's name on chants that she didn't actually compose because the world desparately needed a female composer-hero from the medieval era.
Now, all that aside, I have not heard of some of these recordings of which you all are speaking. Since I teach Music Appreciation, I am always looking for ways to connect students to ancient music (like Gregorian chant). There are artists out there who are recording contemporary rock and pop tunes in the style of Gregorian chant?
Who, where, and how?