Rosemary Sutcliff 
Shield Ring 

Bjorn and Frytha share a bond, both orphans and survivors of Norman attacks on their homes in the Lake country. Growing up together in Jarl Buthar’s Norse stronghold, they become fast friends, with Bjorn dreaming of becoming a harper like his father.As they come of age within this secret fortress, they hear word of the Norman attacks beyond their walls, drawing ever closer to the safety of their home. Can they help protect their adoptive home and family, or will they lose everything all over again?