late to the game, but i highly recommend this book edited by some of scandinavias best scholars in norse and celtic studies - Ideology and Power in the Viking and Middle Ages. gro steinsland, jan erik rekdal and jón viðar sigurðsson (all from the university of oslo in norway) are all rockstars within their field, and the book gives a good view on mythology, ideology and rulership in the viking and middle ages.
you can download the book from academia.edu, or by it from scribd (link is to academia.edu)
*The Penguin Atlas of Medieval History - Colin McEvedy 1961 for an overview. *2008, erudite conference output in Chapters 37 to 40 https://www.amazon.co.uk/Viking-World-Routledge-Worlds/dp/0415692628
My Old Norse professor's translation of the Poetic Edda is fantastic. Check it out here.