Paradoxically, Charlemagne became less important to the Charlemagne legend. The legend became a story about the Frankish people, who believed they had held God's favour under Charlemagne and held out hope that they could one day reclaim their special place in sacred history. Indeed, popular versions of the Last Emperor legend, which spoke of a great ruler who would reunite Christendom in preparation for the last battle between good and evil, promised just this to the Franks. Ideas of empire, identity, and Christian religious violence were potent reagents. The mixture of these ideas could remind men of their Frankishness and move them, for example, to take up arms, march to the East, and reclaim their place as defenders of the faith during the First Crusade.

An Empire of Memory uses the legend of Charlemagne, an often-overlooked current in early medieval thought, to look at how the contours of the relationship between East and West moved across centuries, particularly in the period leading up to the First Crusade.