[De musica met glossen; Enchirias; De organo]

Manuscript 531, dating from the tenth century, was part of the Ten Duinen Abbey library. It contains De musica by Boethius (c. 480-524). De musica is Boethius' work on the theory of music, with a focus on arithmetic in function of tonality and harmony. The notes of Pope Sylvester II (c. 950-1003) are also part of De musica's text in this manuscript. Additionally, there are two more shorter texts a…