Romanticism (also the Romantic era or the Romantic period) was an artistic, literary, and intellectual movement that originated in Europe toward the end of the 18th century and in most areas was at its peak in the approximate period from 1800 to 1850. Partly a reaction to the Industrial Revolution, it was also a revolt against the aristocratic social and political norms of the Age of Enlightenment and a reaction against the scientific rationalization of nature. It was embodied most strongly in the visual arts, music, and literature, but had a major impact on historiography, education and the natural sciences. Its effect on politics was considerable and complex; while for much of the peak Romantic period it was associated with liberalism and radicalism, its long-term effect on the growth of nationalism was probably more significant. The movement validated intense emotion as an authentic source of aesthetic experience, placing new emphasis on such emotions as apprehension, horror and terror, and awe—especially that which is experienced in confronting the sublimity of untamed nature and its picturesque qualities: both new aesthetic categories. It elevated folk art and ancient custom to a noble status, made spontaneity a desirable characteristic (as in the musical impromptu), and argued for a natural epistemology of human activities, as conditioned by nature in the form of language and customary usage. Romanticism reached beyond the rational and Classicist ideal models to raise a revived medievalism and elements of art and narrative perceived to be authentically medieval in an attempt to escape the confines of population growth, urban sprawl, and industrialism. Romanticism embraced the exotic, the unfamiliar, and the distant in modes more authentic than Rococo chinoiserie, harnessing the power of the imagination to envision and to escape.