Feanor4d
King Charlemagne, the first Christian king of Northern Europe waged war against other Northern Europeans, particularly the Saxons (A Germanic pagan tribe at the time). Even though King Charlemagne himself was Frankish, a Germanic tribe as well he changed his identity and culture to Roman and Christian. Thus, he was a notable figure that kickstarted the Romanization and Christianization of Northern Europe, which greatly changed the culture of Northern Europe.