
Percy Shelley was one of the main Romantic thinkers. His second wife was Mary Shelley, the author who wrote Frankenstein. Percy Shelley is most famous for Ozymandias, Ode to the West Wind, To a Skylark, and The Mask of Anarchy.
There is a theory that Percy Shelley was the one who actually wrote Frankenstein and not Mary Shelley because of his firm belief in Atheism.