While much more can always be said, I posted a very basic summary before in: Who were the ruling class of the Viking Age in Scandinavia? Were they chosen by merit, or born into powerful families?

I'll be willing to answer any follow-up question or clarification, but not within 8 hrs today (due to the teaching duty of two classes today).

This issue is also not so simple than generally assumed, as is often the case with this kind of question, since we don't have much evidence on how individual rulers styled themselves (not in later traditions) contemporary.