Dot Porter, Curator, Digital Research Services at the University of Pennsylvania Library, offers a video orientation to Penn Library’s LJS 184, Liber ethimologiarum, by Isidore of Seville. This manuscript was written in France or Catalonia, between 1265 and 1299, in Latin, and it is an encyclopedia with emphasis on word origins, arranged by subject. The manuscript follows the standard division into 20 books, except that Book 3, on mathematics, music, and astronomy, is divided into Books 3 and 4, giving the manuscript a total of 21 books. Additional astronomical material, probably from Bede’s De temporum ratione, appears at the end of Book 21.
See the full online facsimile of this work in Penn in Hand.