Ms. Coll. 591 Item 34 - Collectar leaf
This beauty is a leaf from a collectar, also called a collectarium or capitulary, a liturgical book containing short prayers. The leaf is from early in the manuscript and briefly demonstrates, with texts and square musical notation, how to begin the Divine Office (Modus inchoandi horas); how to chant the chapters (Modus dicendi capitula); and how to chant the prayers for Vespers and Lauds (Modus dicendi orationes in vesperis et in laudibus). The leaf is written in 2 columns of 9 or 10 4-line staves in red ink, with rubrics in red, chant text in black below each staff and marginal notes to the left of the staves in red. It is decorated with one large puzzle initial in red and blue, flourished in purple and red; the remaining initials are either red with purple flourishing or blue with red flourishing. An ornamental border in red and blue decorates the left edge of 3 out of 4 columns on the leaf. It was written in France around 1325 CE.
Time to see the facsimile here (or here for additional information).