Incunabula and the Keio University Library Collection

At universities in the Middle Ages, liberal learning was classified into categories corresponding to the seven disciplines, i.e. the quadrivium (four disciplines), and the trivium (three disciplines), the latter comprising grammar, logic (or dialectic) and rhetoric. The quadrivium consisted of arithmetic (number alone), geometry (number in space), music (number in time), and astronomy (number in space and time), and was based on the classification system for arithmetic created by the Greek mathematician Pythagoras, who defined number as the basic principle of all things.

At that time, Boethius (c. 480-524 CE) was called 'the last Roman who could understand Greek', and this book, the Opera, contains many of the works that he translated into Latin from the original Greek, along with his commentaries on them. The first part, Arithmetica Geometria et Musica Boetii, is one of his early works; it was written at the beginning of the 6th century CE. The music theory found in this book, and said to have been his own creation, became the foundation of Western music; it was recognized as the authoritative text on music theory throughout the Middle Ages. Later, as the range and variety of music evolved in the West, Boethius's music theory gradually waned in influence, and it came to be regarded as unsuitable for the training of musicians. However, coinciding with the rise of universities in the Middle Ages, his work reappeared as the standard text for the academic study of music, which was one of the four elements of the quadrivium.

The Opera consists of Part 1, printed on 18 August 1492, and Part 2, printed on 26 March 1491. Part 2 is a collection of Boethius's Latin translations of Aristotle's works and the annotations that he made on them; it was the sole source of knowledge for the foundation of the Aristotelian school in the Middle Ages. The Keio University Library copy is Part 1, Arithmetica Geometria et Musica Boetii. Every place allocated for a capital letter on its pages is blank, though guide letters are visible. There are abundant woodcut images, figures and tables with Gothic lettering. In the music section, sounds are denoted by numbers representing the frequency of pulsation or percussion using woodcut illustrations; it is considered that the printing required an extraordinary level of skill. What demands our attention and calls for further study is the fact that the signature for quire A was carefully erased and substituted with a new signature on the upper right or left corner of each page. The books that were separately published in parts, like the one in Keio, are extant in great number, but there are fewer examples of combined editions comprising Parts 1 and 2, suggesting that the Opera was originally published in separate parts.


[Bibliography]
  Boethius, Anicius Manlius Severinus, Fundamentals of Music, trans. with notes by Calvin M. Bower, ed. by Claude V. Palisca (New Haven: Yale University Press, 1989)

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