Poul Anderson 
Mother of Kings 

As a child of just seven summers, Gunnhild finds herself fascinated with the powers of a witch-woman who is a concubine of her father’s, a powerful Norse chieftain. She also finds another fascination in handsome and lordly Eirik, son of their king. When her mother dies, Gunnhild promises, "I will never yield", and that, "through me, our blood shall flow greatly".Gunnhild has learned from her chieftain father the way the powerful use the weak. But there are other lessons and other power she seeks. Sent away to learn the magic of a pair of shamans, Gunnhild becomes a Spaewife — a knower of the Gods, a master in the ways of witchcraft and sorcery. Aided by her new abilities, Gunnhild marries Eirik. She is destined to become queen, and her magic is a fearsome complement to Eirik’s strength. But Eirik’s enemies are cunning, and Gunnhild is soon without his might.If Gunnhild can keep the promise she made as a child to never yield, her family’s blood will flow greatly, and the sons she bore Eirik will each become a king. Her own struggles, though, are far from over…