Old Saint Paul's: A Tale of the Plague and the Fire is a historical novel by William Harrison Ainsworth, published in 1841. The story is set in London in the 17th century, during the reign of King Charles II, and tells of the events leading up to the Great Fire of London and the outbreak of the plague. The novel follows a group of characters who live and work in the vicinity of Old Saint Paul's Cathedral. The protagonist is a young man named Leonard Holt, who falls in love with the daughter of a wealthy merchant. The novel also features a range of other characters, including a highwayman, a plague victim, and a witch. As the story progresses, the plague spreads throughout London, causing death and chaos. Meanwhile, tensions between the royalists and the parliamentarians reach a boiling point, leading to the outbreak of the Great Fire of London. Old Saint Paul's is notable for its vivid and detailed depiction of London during a period of great turmoil and upheaval. The novel also explores themes such as love, loyalty, and the struggle for power. Ainsworth's work is considered an important contribution to the historical fiction genre and remains popular among readers interested in the history of London.