Who was she and why did she?

Just arrived in Skellinge and saw the king's funeral. During the funeral there was a young woman crying and when they send Bran off she boarded the boat with him and died with him, why did she do that? And who was she? Daughter? Second wife?. I know Skellinge is based on vikings and they were buried with people but as far as I know those people were mostly slaves and also killed beforehand. I just think it's kind of weird if they never tell us who she are.