by Dorothy Dunnett
Set in Scotland and Orkney, 11th century.
    An unusual theory about the identity of the historical Macbeth, and a convincing 
    portrayal of 11th-century Scotland with its dual Norse and Celtic heritage. 
    Battles, intrigues, family rivalries, betrayals and fate, all told with a 
    laconic wit reminiscent of the Norse sagas. The love story between Thorfinn/Macbeth 
    and his wife Groa/Gruoch, which begins as a political marriage to secure the 
    spoils of war and is forged into a relationship of enduring love and trust, 
    is one of my favourites in fiction.