Although the term steampunk originated in the 1980s, the foundations of the genre go back much further. As is often the case when it comes to defining and categorizing fiction and its genres, opinions differ. But a strong argument can be made that the origins of steampunk lie in what are more commonly considered the earliest science fiction stories, period. The fantastic science and contraptions shown in the works of Jules Verne, H. G. Wells, and Mary Shelley are based in the technology of the 1800s but go far beyond what was actually possible at the time. This advance beyond historical realism is the core of steampunk.