In the summer of 1816, a tour of continental Europe was proposed. At a stop in Switzerland, the couple and Mary's stepsister, Claire, rented a house near another British writer, Lord Byron. The summer proved wet and unseasonable; Byron suggested the group take to writing ghost stories to pass the time. It was during this summer that the form for Frankenstein was to take shape. The story was first only a few pages, but with the encouragement of Percy, the tale took on a greater length. Mary's story, the best of the group, was so frightening to Byron that he ran "shrieking in horror" from the room. Frankenstein was published in 1818.