5 When the sons of King John I asked him to permit the first overseas expedition which liberated the city of Ceuta, that great prince asked them whether or not it would promote the service of God. In like manner, all the following expeditions were especially aimed at propagating the faith. In the West faith had motivated those signed with the cross, and the same faith had animated the military orders who fought strenuously against the Moors.
Source: Saeculo Exeunte Octavo (Vatican.va)