There is a one-panel cartoon, published last year, showing a doctor with the twined snakes of the caduceus on his chest asking a parent to tell her screaming child that he's not part of Slytherin. The cartoonist who wrote the caption doesn't mention JK Rowling or Harry Potter. They're able to assume that the audience will be so well acquainted with the books that they don't need to. Ann Radcliffe's fame was once like that.
It lasted for a long time, too. In Les Miserables, published 40 years after her death, Victor Hugo refers, in an aside, to "the vivid imagination of the police, that Ann Radcliffe of the government." Thirty years later Henry James mentions one of her books in The Turn of the Screw. "Was there a "secret" at Bly," his narrator asks, "-- a mystery of Udolpho or an insane, an unmentionable relative kept in unsuspected confinement?" In both cases the author treats the reader as if they will naturally know what he means. To them Radcliffe was familiar enough to be used as an easy point of reference: as cold as snow, as high as the sky, as Gothic as Ann Radcliffe.
The author of The Mysteries of Udolpho was born in 1764 and died in 1823. She housed her characters in Catholic parts of Europe -- in Italy, in France, places with dramatic landscapes and exotic monasteries -- without ever leaving England. In spite of her fame she preferred to stay out of the public eye. She didn't invent the Gothic novel, but her popularity helped to form the tone of beleaguered high emotion that became one of the genre's defining characteristics. Her language is firm and imporous without being static, her pen has an eye that moves across the landscape:
"To the south, the view was bounded by the majestic Pyrenees, whose summits, veiled in clouds, or exhibiting awful forms, seen, and lost again, as the partial vapours rolled along, were sometimes barren, and gleamed through the blue tinge of air, and sometimes frowned with forests of gloomy pine, that swept downward to their base. These tremendous precipices were contrasted by the soft green of the pastures and woods that hung upon their skirts …"
Her voice is a series of contrasts: clouds and blue air, barren rock and forests, the sharp double-pop of precipice leading into the open-ended sound of pasture and wood. Radcliffe is sensitive to extremes. In her books, sensitivity itself becomes a sign of moral virtue, particularly a sensitivity towards wild, natural places. Her villains are people who have allowed the urban world to coarsen them. They would rather gamble in a casino than look at a forest, and they prefer ostentatious glamour to "modest elegance." Her heroes are the other way around. When Emily's aunt in Mysteries of Udolpho complains that the wild mountains of Italy are "horrid," the reader knows that there is no love for this aunt in the author's heart.
The apparently supernatural events in her books all come with rational explanations. If one of her characters thinks she's seen a ghost then the scene is not there to prove the existence of ghosts, but to give the characters, and, through them, the readers, a chance to be overwhelmed by their feelings. The object of the emotion is less important than the emotion itself. Her oeuvre is like opera in this way -- the plots are preposterous, but the whole thing is done with such luscious self-belief that the audience is tempted to forgive.
Radcliffe is not as well-known as she used to be. In modern editions of Les Miserables, Hugo's reference has earned itself a footnote. No one is likely to make her the punchline of a cartoon. But her fame still survives in odd ways, in hidden signs and signals, like the theatre production that mingled Jane Austen's Northanger Abbey with Udolpho, or a fleeting reference to a castle called Dunbayne in Alan Moore's League of Extraordinary Gentlemen, or the small Gothic publishing house in Kansas whose owners seem to have named themselves after one of her characters. They call themselves Valancourt Books.