Berserkers lived in Scandinavia and served as guards of King Harald I Fairhair, who ruled Norway from 872 to 930 A.D., that much we know. They fought for other kings and royal figures as well.
One notable figure named Gyda was the daughter of Eirik, King of Hordaland. According to legend, she played a significant role in King Harald Fairhair's quest to unify Norway.