Dot Porter, Curator, Digital Research Services at the University of Pennsylvania Library, offers a video orientation to Penn Library’s LJS 47, De institutione musica by Boethius. The manuscript was written in France around 1490 in Latin and it is a copy of a Latin treatise on the Pythagorean-based theory of ancient Greek music, in which the text reflects an older (10th-century) tradition and the numerous diagrams related to ratio and pitch demonstrate later developments in the tradition.
See the full online facsimile of this work in Penn in Hand.
The Schoenberg Institute for Manuscript Studies 
Thank you very much for this, awesome discovery!