Who is Albion Freeman from Storming Heaven: A Novel and what is their importance?

Albion Freeman first meets Carrie Bishop when both are children. While with his father who is a traveling salesman, Albion develops pneumonia and a dangerous fever. His father seeks aid at the nearest farmhouse, which happens to be the Bishop family's Homeplace. Because the local doctor says that Albion must stay in bed for at least a month, his father has no choice but to leave Albion with the Bishops.