Twilight of the Gods
Scandinavian culture, like almost all dark ages cultures, is honor-driven. Honor, and social status, is crucial for survival. Social gatherings are described as a “Game of Honor” by the Icelandic sagas, and can be a source of feuds, alliances, marriages, trysts, and trade.
When conflict comes up, enforcing even the legal decision of a Thing or Assembly requires the support of family and friends. There are no police to arrest anyone, or to come to help if someone attacks your homestead. You might take someone to court, have them found guilty by the Assembly, and be unable to enforce the decision because they have more allies and social status than you do.
This is part of why a character’s holdings are important to define, because those are the allies a character will have available to them.