Here's why:
* Fantasy Elements: They feature magical elements like a tree house that transports readers to different historical periods, talking animals, and fantastical creatures.
* Target Audience: The books are written for children, primarily in elementary school grades.
* Adventure and Exploration: The stories focus on adventure, exploration, and discovery in historical settings.
While they have elements of historical fiction, the strong fantasy elements make them primarily fit into the children's fantasy genre.