Nineteen years later, their son Philip the Handsome married Joanna of Castile, daughter of King Ferdinand II of Aragon and Queen Isabella I of Castile. Joanna (also known as Juanna the Mad) was sister to Katherine (of Aragon), the first wife of Henry VIII of England. Following the death of _her_ brother and two sisters, Joanna became heiress to the Spanish throne. <sep>, Pronoun: her <sep>, A: Katherine <sep>, B: Joanna