Christ's war reveals that the Carolingians waged holy warfare when their armies fought in a sinless state of righteousness and God, accordingly, granted them victory. The Franks thus forged their eighth- and ninth-century empire through a vision of holy war that differed from the apocalyptic military pilgrimages of the subsequent Crusades. Comparing battle narratives with theological, liturgical and sermon literature, this book explores how Carolingian notions of holy war shaped their military successes and conquests during the empire's rise under Charles Martel and King Pippin, and thereafter Frankish holy war took its fullest expression under Emperors Charlemagne and Louis the Pious.

Yet Christ's war also shows how civil war and humiliating defeats by the Northmen caused the Carolingians to blame such disasters on the impiety of their commanders and soldiers later during the ninth and early tenth century. Nevertheless, victorious leaders and their armies continued to be celebrated for their holiness, which brought divine favor on the battlefield.

Key among the sources examined here is Latin poetry, since warfare found its most dramatic expression in verse. Correspondingly, this study also investigates how poets and other inventive authors crafted their narratives with powerful emotions, graphic violence and horror imagery to enrich the audience's imaginative experience of victory or defeat. In this fashion, Carolingian audiences participated vicariously in holy war as a pious literary pleasure. Christ's war offers these important insights into the religious nature of Frankish warfare, while also contributing a fresh and innovative perspective on medieval holy war.