Lettre ornée Guillaume de Machaut, Messe Reims, vers 1372-1377 Paris, BNF, département des Manuscrits, Français 1584, fol. 448v.
Sumer is Icumen In (Summer is coming!) an old folk song written as a round in 6 parts. The song was famously used on the film "The Wicker Man".
I was digging through the early manuscripts in Latin on the bnf website, and found this. I couldn't figure out what the dots were, and then it struck me! Music! This is fantastic, and I need to show it to the choir guild. Troparium et prosarium Sancti Martialis Lemovicensis 0975-1100
Guillelmus a Mederio , Calendarium sive Commemorationes sanctorum monachorum , Missa et officium sanctarum reliquiarum , Officia sancti Georgii et sanctae Marinae
Initial C: The Creation of the World. MS. 24, LEAF 5 Artist unknown, Italian, circa 1420, tempera colors, gold leaf, and ink on parchment. 18-5/16" x 13-5/8" From: CEREBRAL BOINKFEST: A Marriage of Painting, Writing, and Music: Illuminated Choir Manuscripts