"The Marchioness" is Dick Swiveller's name for the little servant girl who lives below stairs at the law firm of Sampson and Sally Brass. When Swiveller comes into his inheritance he pays to educate the Marchioness and renames her "Sophronia Sphinx." They eventually marry.
Joseph Clayton Clark,"Kyd." The Characters of Charles Dickens. London: Raphael Tuck, 1890.