The following pages have been written amidst many interruptions and completed amidst great difficulties. The excuse for their existence is to be found in the total absence of any adequate biography of their subject, and the attraction (to the author at any rate) of a varied and interesting career. My indebtedness to those who have made a study of the fifteenth century is acknowledged in the bibliography, but my obligations extend much further. My thanks are due to many librarians who have given me every facility to inspect manuscripts in their care, but to Mr. Falconer Madan of the Bodleian Library at Oxford I am under no ordinary debt of obligation. His consistent kindness and interest has made many paths smooth that would otherwise have been rough. I am indebted to Lord Leicester for his kindness in allowing me to examine a manuscript life of the Duke which forms part of his Library, and to Mr. Yates Thompson for a similar permission with regard to the Duke's Psalter. Still more do I desire to thank Dean Kitchin for his courtesy and kindness in sending me a transcript of a letter in a Durham manuscript, whilst Professor Oman has given me the great encouragement of his sympathy and advice. To Dr. Morris of Bedford I owe assistance on some points of difficulty, and Sir Alfred Scott-Gatty, Garter, was kind enough to answer several questions with regard to the Duke's armorial bearings. To my mother, who has spent many weary hours in copying my manuscript; to my sister, who is largely responsible for the index; and to my friend, Mr. H. W. Ward of Frenchay, whose assistance, both clerical and critical, has been freely given, the mere record of my gratitude is not sufficient.