About the book (from Wikipedia):
The Tower of London is a novel by William Harrison Ainsworth serially published in 1840. It is a historical romance that describes the history of Lady Jane Grey from her short-lived time as Queen of England to her execution.
The plot begins with Lady Jane Grey, wife of Guilford Dudley and daughter-in-law to the Duke of Northumberland, as she enters the Tower of London on 10 July 1553. Prior to her entrance into the Tower, she ruled as Queen of England for nine days after she and her husband were put on the throne by the Duke of Northumberland. Soon after, Mary I was able to take control of England and sent the Duke to be executed. Dudley, to gain back the kingdom, formed a rebellion, which results in failure and the imprisonment of both himself and his wife. After the imprisonment, Simon Renard, the Spanish Ambassador to England, arranges a marriage between Mary and Philip of Spain to bring a Catholic take over of England.