I've been listening to...Montségur: La Tragédie Cathare by Quebec ensemble La Nef. I don't have much in the way of medieval music, but what little I have I enjoy very much, and this collection is wonderful. I love the sounds of pipes, shawms, recorders, it's all so evocative of a bygone era.
The theme of the CD is the 'heretical' sect of the Cathars, a gnostic/dualist religion centred in Southern France and Italy. Related in belief to the Bogomils of Bulgaria and possibly (there is some debate) descended from Manichaeism.
The liner notes indicate that little is known of Cathar music, but the the selections chosen reflect the area (Languedoc) and time period and are from the repertoires of contemporary troubadours.
For more information on the Cathars: https://en.wikipedia.org/wiki/Catharism
La Nef: https://lanefeng.com/
Any further suggestions of medieval music would be very welcome.