In 1817, Shelley produced Laon and Cythna, a long narrative poem that, because it contained references to incest as well as attacks on religion, was withdrawn after only a few copies were published. It was later edited and reissued as The Revolt of Islam (1818). At this time, he also wrote revolutionary political tracts signed “The Hermit of Marlow.” Then, early in 1818, he and his new wife left England for the last time. During the remaining four years of his life, Shelley produced all his major works, including Prometheus Unbound (1820). Traveling and living in various Italian cities, the Shelleys were friendly with the British poet Leigh Hunt and his family as well as with Byron.