This book is the first account of the period to consider both Christian and Muslim Spain. The author discusses the various societies, cultures and governments of Muslim and Christian Iberia in the centuries of their critical confrontation. Beginning with the disintegration of the caliphate at Cordoba in the early eleventh century, the book traces the decline of the Muslim taifa states, and describes and explains their conquest, first by the Murabit, and then the Muwahhid fundamentalist Muslim empires of North Africa.

Bernard Reilly describes the rising Christian kingdoms of Leon-Castilla, Aragon, Barcelona and Portugal and shows how they were engaged in a struggle on several fronts. As they vied with one another for control of the old Islamic stronghold of the center and north, they were also in continuous conflict with the Murabit and Muwahhid rulers, while striving to come to terms with the French, the Papacy and the Italian maritime powers.