In 1025 the Byzantine Empire was the greatest power in the Mediterranean and Near Eastern worlds, and its capital Constantinople the most glittering city; in 1204 Constantinople fell to the Fourth Crusade. Although Byzantine rule was restored to the capital half a century later, and the revived empire continued for another 200 years, the political ascendancy of Byzantium was gone for good and with its disappearance the centre of gravity of Christendom shifted irreversibly westward. The crucial period leading up to the debacle of the Fourth Crusade was thus a watershed not only for Byzantium itself but for the whole mediaeval world. There has long been a need for a detailed and authoritative account of it within the scope of a single volume, which Michael Angold’s splendid work now provides. The story he tells is not one of inexorable decline. It is instead a study of transformations in both government and society which brought grave weaknesses along with great benefits. These transformations were necessary because the centralised Byzantine government machine was breaking down under the pressure of economic and social change, as the growth of trade and manufacturers led increasingly to the dominance of the cities in the life of the empire. The emperors came to rely less on a bureaucracy and more on a hereditary aristocracy. The structure of the state became less and less solid, but it enabled the emperors to come to terms with the developments which, in the later 11th century, were already threatening the survival of the empire: the Turks seized Anatolia, the Petcheneks seized the Balkans, and the Normans of Italy were hammering at the gates of Greece. These encircling dangers were complicated and intensified by the appearance of a new phenomenon the crusades. The Byzantines responded to these threats by attempting to bring their enemies more closely within the orbit of the empire. In the short term this worked: Constantinople and the empire had never seemed richer or more powerful than in the mid-years of the 12th century. But the longer term penetration of foreign elements into the very structure of the state proved disastrous, and disaster came with the Crusade of 1204. The events of these two centuries are complex in their causes, courses and consequences alike, but Michael Angold does them full justice in this richly detailed and absorbing account. The book is primarily a political history, but the connections between political and social, economic and cultural developments are emphasised throughout. Michael Angold read history at Oxford University and has taught mediaeval and Byzantine history at the Universities of York and Edinburgh.