Contains historical information on the foundation of the Convent of St Clare in Brussels (f. 144v), a calendar, Propers of the Time and of the Saints, Common of the Saints, various Offices, and various other liturgical texts. Several pages contain music notation: 1v-2v and 149r-152r Benedicamus Domino settings and 138r-144r (responds for the Office of the Dead). Of the more than 30 monophonic Benedicamus Domino settings, most are troped and most are set to the flos filius melisma, a common melody for Benedicamus Domino setting. Concordances are found in numerous MSS from the 14th and 15th centuries, including a highly ornamented verson in Las Huelgas (21v-22r). Immediately following the setting in BR 1870 (on f. 1v) is an arrangement of the two voices that results in a narrower range for both parts - a 6th in both voices rather than an 11th and a 12th as in the original. The two voices for the second version are notated in score format rather than consecutively and are linked by an arc, connecting the two staves. Since no concordances were found for this arrangement, on might presume that the sisters of St Clare have made their own arrangement of the setting, one that fits the available voices more comfortably.

1v-2v