The Vikings came to be convinced that the Christian God is more powerful than all other gods.
They saw how He answered the prayers of the Christians.
They witnessed miracles.
They saw how Christian kings and missionaries were able to destroy idols, and defy the heathen gods and taboos; without suffering any ill effects.
They saw that their pagan gods were powerless before the all powerful Jesus Christ.
Christ was honored and worshiped as the Mighty Warrior who has triumphed over all the powers of death, hell and the grave.
He is the risen ascended Christ, King of kings, and Lord of lords; with all other authorities in subjection to Him.
“Yes, all kings shall fall down before Him; all nations shall serve Him.” Psalm 72:11
The prominence of the Cross in every Scandinavian flag serves as a dramatic testimony to the conversion of the Vikings.
