Julia Fox is an author and historical researcher, and a former teacher. She lives in London with her husband, the Tudor historian John Guy. Her first book was Jane Boleyn: The Infamous Lady Rochford, a study of the lady-in-waiting at the court of Henry VIII of England and the sister-in-law of Anne Boleyn. Her second book, Sister Queens, is a biography of sisters Katherine of Aragon, who was Henry VIII's first wife, and Joanna of Castile, who was the mother of Charles V, Holy Roman Emperor.