Son of British Prime Minister Robert Walpole, Horace Walpole was a prolific letter writer, memoirist, poet, dramatist, novelist, antiquarian, and critic. He is best known for inaugurating the Gothic novel with The Castle of Otranto (1764), a tale of aristocratic decadence, incest, and the supernatural. He privately printed and circulated among his acquaintances copies of a second gothic work, The Mysterious Mother (1768), this time a blank verse tragedy on the theme of Catholicism and incest. His biographical account of Roger Boyle appears in A Catalogue of the Royal and Noble Authors of England, With Lists of Their Works (1758). Walpole's other works include Anecdotes of Painting, enlarged from Vertue (1762) and An Essay on modern Gardening (1780). Walpole is also well known for his "little jeu d'esprit" with Jean-Jacques Rousseau. One of Walpole's publicly circulated letters to David Hume openly mocked what Walpole perceived to be Rousseau's self-important nature. The letter offered a spurious invitation to Potsdam from the King of Prussia to Rousseau. The letter caused quite a stir among British and French high society. Walpole succeeded as the fourth Earl of Orford in 1791 on the death of his nephew George Walpole, the third Earl of Orford.