Kristin Lavransdatter is the common name for a trilogy of historical novels written by Nobel laureate Sigrid Undset. The individual novels are Kransen (The Wreath), first published in 1920, Husfrue (Wife), published in 1921, and Korset (The Cross), published in 1922. Kransen and Husfrue have also been published in English translation under the titles The Bridal Wreath and The Mistress of Husaby.
This work formed the basis of Undset receiving the 1928 Nobel Prize in Literature, "principally for her powerful descriptions of Northern life during the Middle Ages"; her work is much admired for its historical and ethnological accuracy.
This quotation is taken from
http://en.wikipedia.org/wiki/Kristin_Lavransdatter
It is not Vikings, but what they became. The first book is still very readable.