Warrior Woman - English Dawn, #3

A tomboyish girl, fond of stories of shieldmaidens and waelcyries, gets involved a viking raid led by her older brother. The raid goes wrong, and her stepmother tries to teach her that her 'womanly weapons' have more power. She goes on to seduce one king of Britannia and kill another, thus playing as large a part in the conquest of that country as her father, Hengest - but can she ever find true love? This is the third part of the English Dawn pentalogy, which tells the story of the conquest and settlement of Britain by the Anglo-Saxons in the 5th century, set against the broad sweep of events in the Dark Ages: the decline of the Roman Empire, the rise of Attila the Hun, the raids by the Picts and the Scots, and the usurpation of the kingship of Britannia by the tyrant, Vortigern.
These events are a prequel to the age of Arthur, and the final chapter of the pentalogy sees Merlin setting up the sword in the stone for the king who is to come.