I am deeply indebted to an enormous number of people who have helped me in the writing of this book. In 1995 I was able, through the generosity of the British Academy, to travel in Italy and much of the Middle East. Subsequently, with help from the University of Wales, Swansea, I went to the Lebanon and revisited Syria. During these travels a large number of people provided a lot of practical help. In Italy, I would like, in particular, to thank the local authorities at Manerbio and Frascati, whose officers went out of their way to put their local knowledge at my disposal, and the librarians at Avezzano who took so much trouble over my queries. Peter Clark and his colleague, Hadeel Alahmad, at the British Council in Damascus were immensely helpful. Dr Alison McQuitty, Director of the British School at Amman, provided hospitality and helpful advice, as did Dr R. Harper, Director of the British School at Jerusalem, who also laid on a memorable tour of castles. Dr Mohammed Moain Sadek, Director of Tourism and Antiquities for the Palestinian National Authority, was kind enough to escort me around some fascinating sites in Gaza. In all these countries and others I was received with great kindness, for which I offer thanks.
I must acknowledge great debts in terms of ideas. Professor J. C. Holt, though writing in a different context, first fixed my mind on the importance of landed property. I owe a great deal to the ideas of Professor John Gillingham, whose work on war has been so influential. It was thanks to Professor Bernie Bachrach that I was invited to address the Haskins Society at Houston, providing me with an opportunity to sharpen my ideas at a critical time: as a result of these discussions I owe a particular debt to Professor Richard Abels and Dr David Crouch. Kelly de Vries is a splendidly robust person to try ideas out on. Ronnie Ellenblum of Hebrew University was kind enough to share with me his enormous knowledge of crusader archaeology,