While the Eddas and the Sagas do hold a great deal of clues and possible insights into the Religious Customs of the Viking Age Norse the fact is by the time they were written down Christianity had been the official faith of the land for more than 200 years. Now that is not to say that much of the lore isn't useful or doesn't reflect Viking Age Religious beliefs. However if one is to base their understanding of Viking Age religion on the evidence, literary and archeological, than the chances of those twelve actually being Goddesses in the minds of the Viking Age Norse is rather suspect. In fact it would appear that the Pantheon of "Major Deities" was a bit smaller than the Eddas make it seem, and nowhere near as organized.
Thus far the Gods that Historians do know played a major role were Odin, Thor, Frigg, Tyr, Ullr, Skadi, Freya, Freyr, and Njord. I believe I remember reading somewhere that some suspect that the names of those twelve Goddesses were simply titles for Frigg. Also another thing remember. How the Viking Age Norse viewed them probably wasn't as strict as the Eddas make it seem. Norse Religion was far more complex and diverse than that. If anyone is interested in a few good secular titles on the subject I would recommend Rudolf Simek's Dictionary of Northern Mythology which not only covers Norse but continental Germanic and Anglo-Saxon material as well. Also I would recommend The Mead Hall. I forget the Author's name but it does give one a great deal of insight into the minds of "Dark Age" Germanic cultures. Another good title is Gods and Believers by Thor Ewing. I don't believe the man is a professional academic but his passion and knowledge of the subject does shine through and in my opinion I believe he gives a good summary of what all evidence seems to suggest about Viking Age Religious Customs and Beliefs. However if your looking for more in depth titles than this one is probably not what you want.
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