It is our part with the help of Divine holiness to defend by armed strength the holy Church of Christ everywhere . . . it is your part, most holy Father, to help our armies with your hands lifted up to God like Moses, so that by your intercession and by the leadership and gift of God the Christian people may everywhere and always have the victory over the enemies of the Holy Name.

— Charlemagne, in a letter to Pope Leo III, 796 AD