“Behold, a people shall come from the north, and a great nation, and many kings shall be raised up from the coasts of the earth. They shall hold the bow and the lance: they are cruel, and will not show mercy: their voice shall roar like the sea.” Jeremiah 50: 41-42
This passage of the Bible, and others like it, were on the minds of the literate men of the church in the 9th century And you can see why, can’t you? The Christian nations of the west, even their monasteries and other religious houses, were being attacked by pagans. By the enemies of god himself. The vikings seemed to be the fulfillment of a dark prophecy.