This book is a revised version of a Ph.D. dissertation written at Yale under the direction of Rulon Wells, to whom I shall always be grateful for showing me the value, and beginning to teach me the art, of asking interesting questions about anything and everything.

It must also serve as a memorial to the late Professor Jan Pinborg, Director of the Institute of Medieval Greek and Latin Philology at the University of Copenhagen, who took a great interest in it and provided me with much help while it was being written, but unfortunately did not live to see it published. His last communication to me, just a few weeks before he died, was a detailed set of comments on my dissertation; they were invaluable in preparing the present version.

This work would not have been possible without the aid of National Science Foundation Grant Number BNS-81-05359, which enabled me to travel to Europe, examine manuscripts, confer with scholars, and assemble a microfilm collection. Many people offered assistance and advice along the way; some who deserve special thanks are R. H. Robins (University of London), Bruce Barker-Benfleld (Oxford), W. Keith Percival (Kansas), Irene Rosier (CNRS, France), C. H. Kneepkens (Nijmegen), K. M. Fredborg (Copenhagen); the two additional readers of the original dissertation at Yale, Edward Stankiewicz and C. J. Herington; and P. H. Matthews, who served as reader for the Cambridge University Press. All conclusions and opinions expressed here are of course my own and do not necessarily reflect the views of any of the people acknowledged here, nor of the National Science Foundation or any other governmental agency.