[vii] This book is related to my earlier study of The Episcopate in the kingdom of León in the twelfth century published in 1978: it has grown out of the same concerns; it has at once a narrower focus and a longer reach; it is intended for a different readership. I have written it at home, in odd moments of leisure, over a period of four years and more. This desultory mode of composition will have made a book always intended to have something of a discursive character even more rambling than it might otherwise have been. For this and other shortcomings arising from the circumstances of composition the reader's indulgence is asked.

That the book was completed at all is owing more than I can express to my wife Rachel. She has fed me, left me alone, shielded me from interruption, and in the most selfless way simply put up with me during the hard slog, the bouts of depression, the moments of elation, which attend on authorship. I thank her from the bottom of my heart.

To compose a work of this kind in an isolated farmhouse in the depths of the North Riding of Yorkshire, far from a good academic library, is to ask for trouble. It is also to contract many debts. The final stages of my preliminary research were made possible by a generous grant by the British Academy from the Small Grants Research Fund in the Humanities: I am most grateful for this assistance. In the course of writing the book I have incurred many debts to scholars who have kindly sent me copies of their books or articles. These I have acknowledged at the appropriate place in my footnotes. There remain many friends who have with great generosity helped me by answering questions, checking references, procuring photocopies, buying books for me, and (not least) by giving me hospitality on my journeys southward. I wish in particular to thank the following: in Spain, Don Antonio García y García, Professor of Canon Law at the Universidad Pontificia of Salamanca; in Cambridge, Peter Linehan; in London, George and Avril [viii] Hardie, Philip Mansel and Michael Weinstein; in Oxford, James Campbell, Jeremy Catto, Eric Christiansen, Joe and Rosalind Pennybacker, and Christopher Tyerman.

The dedication of this book is the expression of a debt which is less easy to particularize. I met Denis Bethell in Oxford in the early months of 1966, at a time when I was reading the Historia Compostellana for the first time. He was unusual, then, quite possibly unique, among English medievalists, in knowing well that puzzling and tantalizing text. (I believe that he had been drawn to it initially by the information it provides about the circumstances of the disputed papal election of 1130.) It was a period when I needed encouragement: this he gave me unstintingly. Our meeting ripened into a friendship which was sunned by far more than a shared concern with the ecclesiastical history of the twelfth century. The rhythms of our lives sundered us; he to Dublin, I back to Yorkshire: an intermittent though lively correspondence and some occasional meetings linked us. (His letters, infrequent, entertaining, a shade poignant, were shot through with agreeable misunderstandings. For some reason he was convinced -- despite my denials -- that I was a breeder of springer spaniels, and would enquire solicitously about the state of my kennels.) It so fell out that I saw much of him during the last year of his life. And it was while he was, staying with me, only a few weeks before his death, that I showed him some chapters of this book in draft. The comments that he made on that occasion, kindly, acute and learned (as his criticisms always were) I have borne in mind in revising the work for publication. In dedicating it to his memory I remember a fine scholar, a selfless friend and a good man.

                                                                                                                                                                           Nunnington,
                                                                                                                                                                                       York
                                                                                                                                                                     December 1982