Although the Crusades are generally thought of in terms of the European attempt to conquer and colonize the Holy Land, from the twelfth century onward crusading also involved the "reconquest" of the Iberian peninsula from the Muslims. This eyewitness account of the capture of Lisbon in 1147 by the combined forces of King Alfonso Henriques of Portugal and a fleet of crusaders from the Anglo-Norman realm, Flanders, and the Rhineland is one of the richest and most exciting sources to survive from this period. Far more than just a narrative, De expugnatione Lyxbonensi vividly conveys the tensions between the secular and spiritual motives of a crusading army, as well as revealing a wealth of information on medieval warfare, the development of crusading ideology and holy war, and Muslim views of the crusaders.

The new foreword by Jonathan Phillips provides insight to the latest scholarship on the integral place of the Lisbon expedition in the Second Crusade, the identity of the text's author, and his message for crusaders.