Beginning in the late 18th century and lasting until the middle of the 19th century a new Romantic attitude began to characterize culture and many art works in Western civilization. It started as an artistic and intellectual movement that emphasized a revulsion against established values (social order and religion). Instead Romanticism exalted individualism, subjectivism, irrationalism, imagination, emotions and nature, it valued emotion over reason and senses over intellect. These artists and philosophers of the time were in revolt against the existing social order and they favored the revival of potentially unlimited number of artistic styles (basically anything that aroused their senses or imagination).
The Romanticist movement started as a reaction to the political turmoil of the times, plus the influx of foreign art coming from Canada, Asia and around the world. As such ‘Orientalism’ had a huge influence on the artists of the time, especially artists like Eugene Delacroix.(Ref)
Romanticism Part 1 and 2 by Kenney Mencher