Wondering if there is an online (and free or open source) database/collection of Latin Church music. By that I mean, Gregorian Chant type stuff like this, other monophonic chanting (stuff from 1000-1500CE), or even modern liturgical stuff like the latin songs you would hear in a large Church today (I'm not sure what these really sound like or if they are polyphonic or not). But basically some sort of melodies in the Latin churches. It sounds like it could be polyphonic as well.
Basically just looking for any available sheet music for stuff like that.