==== Motiver ====
De motiver, der drev vikingerne ud, er genstand for debat i nordisk historie. En udbredt teori er, at [[Karl den Store]] "brugte magt og terror til at kristne alle hedninge", hvilket betød [[dåb]], omvendelse eller henrettelse, og derfor ønskede vikingerne og andre hedninge hævn.<ref name="Rudolf Simek 2005, pp. 24">Rudolf Simek, "the emergence of the viking age: circumstances and conditions", "The vikings first Europeans VIII–XI century—the new discoveries of archaeology", other, 2005, pp. 24–25</ref><ref>Bruno Dumézil, master of Conference at Paris X-Nanterre, Normalien, aggregated history, author of conversion and freedom in the barbarian kingdoms. 5th–8th centuries (Fayard, 2005)</ref><ref name = "annals R.20">"Franques Royal Annals" cited in Peter Sawyer, "The Oxford Illustrated History of the Vikings", 2001, p. 20</ref><ref>Dictionnaire d'histoire de France, Perrin, Alain Decaux and André Castelot, 1981, pages 184/185. {{ISBN|2-7242-3080-9}}.</ref><ref>"the Vikings" R.Boyer history, myths, dictionary, Robert Laffont several 2008, p96 {{ISBN|978-2-221-10631-0}}</ref> Professor Rudolf Simek skriver, at "det ikke er et tilfælde, at den tidligste vikingeaktivitet skete under Karl den Store regeringstid".<ref name="Rudolf Simek 2005, pp. 24"/><ref>[[François-Xavier Dillmann]], "Viking civilisation and culture. A bibliography of French-language ", Caen, Centre for research on the countries of the North and Northwest, University of Caen, 1975, p.19, and "Les Vikings: the Scandinavian and European 800–1200", 22nd exhibition of art from the Council of Europe, 1992, p. 26</ref> Kristendommens udbredelse i Skandinavien ledte til stor konflikt i Norge, som delte kongeriget i næsten 100 år.<ref>"History of the Kings of Norway" af Snorri Sturlusson oversat af Professor i History François-Xavier Dillmann, Gallimard {{ISBN|2-07-073211-8}} pp. 15–16, 18, 24, 33–34, 38</ref>
Historie