In this study of the cult and iconography of Byzantine warrior saints, Christopher Walter delineates their origins and development as a distinctive category of saint, showing that in its definitive form this coincides with the apogee of the Byzantine empire in the 10th-11th centuries. With a repertory of their commemorations and representations, he sets out their iconographical types and the functions ascribed to them in the celestial army, supporting the terrestrial army on the offensive, and gaining a new protective role when it moved to the defensive. Features noted are the development of an echelon of military saints, notably in church decoration, which provides the surest basis for defining their specificity; and that their depiction, besides showing them as young, handsome and robust, resorted to twinning them in pairs, calling attention to the camaraderie of soldiers. The work also opens a new perspective on the military history of the Byzantine Empire. The Byzantine ideology of war is seen consistently to follow that of the Israelites; protected and favoured by divine intervention, there was no need to discuss the morality of a just war ; and when considering Byzantine methods of warfare, due attention should be given to the important role they attributed to celestial help in their campaigns.