Beginning in June??? 1816, Mary and Percy Bysshe Shelley, along with Byron, Polidori, Claire Clairmont, and Matthew "Monk" Lewis, spent several months??? in the Maison Chapuis and the Villa Diodati, both on Lake Geneva.
Mary Shelley discusses this stay in the Introduction to the 1831 edition of Frankenstein (Introduction 4). It was a "wet, uncongenial summer" (Introduction 5 and note); the group passed the time in various literary recreations: Lewis, for instance, read and translated parts of Goethe's Faust to Byron. They also read "some volumes of ghost stories" (Introduction 5) -- that is, Jean Baptiste Benoît Eyriès's Fastasmagoriana (Paris, 1812), translated as Tales of the Dead (London, 1813). Byron suggested a contest in which each would write a ghost story. Byron produced "A Fragment," Mary Shelley in the 1831 Introduction describes her efforts "to think of a story" (Introduction 7), and describes the breakthrough of her "waking dream" of "the pale student of unhallowed arts kneeling beside the thing he had put together" (Introduction 10). The initial inspiration eventually became the opening of the fourth chapter.