Many intellectuals, rightly or wrongly, associated the Enlightenment with the intellectual hubris and eventually the excesses of the French Revolution. As such, they gravitated to the broad critique of the Enlightenment that was Romanticism. Political thinkers, rather than emphasizing universal rights, as the philosophes had, began to think of humanity as being organically and historically rooted to their circumstances. While they could, and should, struggle for rights, these rights were understood as part of a shared experience. Naturally, this way of thinking, which was part and parcel of romanticism, bled into the major political trend of the first half of the nineteenth century, nationalism. Because the Romantics tended to view progress as agonistic, requiring struggle, they reacted with joy and fascination to the nationalistic revolutions that swept Europe beginning with the 1820s. Perhaps the most conspicuous example of this trend would be Lord Byron, who went to Greece to fight in their nationalist revolt against the Ottoman Turks, a cause many Romantics adopted as their own. In short, Romanticism was conservative philosophically in many ways, but not necessarily politically.
The Realists responded to the conditions found in the new, modern cities that were a by-product of the Industrial Revolution. Eschewing the classical themes that fascinated eighteenth-century painters and writers and the soaring Sturm und Drang as well as the bucolicidealization of nature that characterized the Romantics, they painted and wrote about people as they were. One contemporary observer described the work of French Realist painter Courbet as
irony directed against our industrialized civilization ... which is incapable of freeing man from the heaviest, most difficult, most unpleasant tasks, the eternal lot of the poor...
Similarly, the works of Balzac, Zola, and Balzac described poor people living in squalor and trying to make the best of their lives. Like Karl Marx, who managed to be both a material realist and a Romantic at the same time, they wrote and painted in response to the conditions created by the modern forces of industry and capital.