The Author's Note says: "This novel is based on fact: The cast of characters, Sisi, Bay, Charlotte, Earl Spencer, and even Chicken Hartopp are all real, even if their thoughts and feelings have been supplied by me." What do you think of the mixture of history and fiction here? At what point did you become aware that the characters were based on real-life individuals, and did it change your opinion of the novel? (One fascinating footnote: In real life, Lady Blanche Hozier's daughter Clementine, whose paternity has been much debated, grew up to marry Winston Churchill.)