While searching for something else entirely, I accidentally ran across a repurposed parchment flyleaf fragment in a 1502 book in the Münster Universitäts- und Landesbibliothek digital collections which contains two-part Notre Dame polyphony. It is listed as Inc 879 in their catalog (though technically not an incunabulum, I suppose, becasue of its date).
https://sammlungen.ulb.uni-muenster.de/hd/content/pageview/6517973
https://sammlungen.ulb.uni-muenster.de/hd/content/pageview/6517974
Perhaps this is a known source, but is not among the fragments of Notre Dame polyphony located in the same library listed by Eva Maschke in her 2015 article 'Some Preliminary Observations on the Afterlife of Notre Dame Fragments' in Manuscript Cultures No. 8, so I am posting it here in case it is unknown and of interest to someone researching that period.
The musical fragment on the verso is the start of Alleluia; Nonne cor nostrum - providing a concordance with the Medici Antiphoner (F), f.110r-111r.
On the recto of the fragment is the end of Alleluia; Epulemur in azimis sinceritatis - which also precedes Nonne cor in F - but this fragment seems to be more textually concordant with the composition as it appears on f. 28v of Wolfenbüttel W1.
Anyway, enjoy!
-Richard
Replies
Magnifique !!!!
Bravo Richard !