It's difficult to assign a genre to this, but my instinct is to ascribe it to historical fiction. It's often put under non-fiction, and biography, but these stories of her ancestors are really quite fictionalised, it seems to me - in their thoughts and emotions and so on. Just because a story's about a historical personage doesn't make it strictly biographical, I think. Certainly the biographies I read tend to have more of the reference about them.

Either way, it's an interesting read. The family members are certainly entertaining characters!