ABSTRACT
In many ways this book is a celebration of the diversity of Europe. In the Middle Ages Catholic Christendom grew because it was fragmented. As a result of bitter competition for limited resources, some of its competing forces extended their conflicts into the world beyond its frontiers. There was not one, but many expansions, and as a result little focus or control. The crusade was an attempt by the papacy, the only universally recognised authority in this area, to control the impulse to grow and conquer. It was not successful. Jerusalem was liberated and provided enormous prestige, but it could not be sustained as a Latin colony in a hostile environment. The papal project was possible because the antagonistic forces within Catholic Christendom had a substantial religious and cultural unity, and it failed because this could not be translated into a single political reality. There was nothing inevitable about the downfall of this idea of unity. Europe was no more diverse in terms of peoples and traditions than the Middle East. It looked back to the Roman Empire when all its peoples were ruled by a single emperor, and more recently the Carolingians had replicated this situation. But the papacy sought to achieve its leadership by ideological means – by developing a notion of spiritual dominion and by presenting Jerusalem as the golden key to heaven. This was quite effective, but ultimately not enough of the potentates of Europe developed a vested interest in the achievement of these ends. This book is largely, therefore, the history of a failure, but it is a failure with enormous consequences and vast achievements, so it is a story worth telling.
