>This affection we and you owe to each other in a more peculiar way than to people of other races because we worship and confess the same God though in diverse forms and daily praise and adore him as the creator and ruler of this world.
St. Gregory VII, Letter XXI to Anzir (Nacir), King of Mauritania; translated by Ephraim Emerton in "The correspondence of Pope Gregory VII: selected letters from the Registrum", Octagon Books, 1966.