Gregory, Philippa. Plantagenet and Tudor novels.

Three sisters. A family of secrets -- and tragedy. Jane Grey was queen of England for nine days. Crowned instead of the dead king's half-sister Mary Tudor, who mustered an army, claimed her throne, and locked Jane in the Tower of London, and sent her to the executioner's block. Her younger sister Katherine is heir to the insecure and infertile Queen Mary and then to her sister Queen Elizabeth, but is imprisoned when her secret marriage is discovered. The youngest Grey sister, Mary, is a beautiful dwarf, disregarded by the court and acutely aware of the danger. What will happen when the last Tudor defies her ruthless and unforgiving cousin Queen Elizabeth?