Gradual or antiphonary
The versos show music on a large red 4-line staff and text in a gothic rotunda hand.
Book Decoration and Musical Notation
Drawn in tempera and colored inks with gold leaf.
De Ricci, 1050.
A. Melograni in Storia dell'arte 82 (1994): 283-302, specif. p. 291 illustrating both initials.