This book has been an unconscionable time in preparation, and one can only hope that it is the better for it. Written over a number of years, in a number of places, various institutions (willingly or unwillingly) bear some responsibility for its existence: the Fitzwilliam Museum, Cambridge; the Barber Institute of Fine Arts and the Department of Mediaeval History, University of Birmingham; and the Dumbarton Oaks Center for Byzantine Studies, Washington, D.C.; to name only the main ones.

In the course of the text, I have attempted to quote, verbatim and extensively, as many of the major primary sources as is possible and as seems relevant. I have done this because a number of them have not previously been rendered into a modern language, or, even if they have been so rendered, are still not readily accessible. I thus hope to have made them accessible to students and amateurs who lack the necessary languages, or the academic facilities, or both. This has meant that, in many cases, and with some trepidation, I have had to do the translating involved myself. In doing so, I have attempted to retain the original form and flavour in as far as it is possible, and particularly where the ponderous, allusive, and elliptical pomposity of imperial legislation is concerned. On the other hand, I have felt little hesitation in changing the moods or tenses of verbs where I have thought it necessary the better to indicate a particular modern sense, or to retain a reasonable linguistic facility.