The romantics’ enthusiasm for the Middle Ages in general and for the earlier history of their own nations in particular linked the universal (nature) to the particular (the nation-state). Nationalism was an emotional, almost mystical force.
The romantic return to the national past, though intensified by French expansionism, had begun before 1789 as part of the repudiation of the Enlightenment. The pioneers of romanticism tended to cherish what the philosophes detested, notably the Middle Ages and the medieval preoccupation with religion.
