In 1800, Europe comprised some five hundred political units, varying hugely in size and viability; by 1900 there were only about twenty.

From The Long Shadow by David Reynolds.  Page 4.

What is a nation? The French intellectual Ernest Renan posed that question back in 1882, and the debate still rumbles on. People’s sense of identity can take many forms, defined by gender or class or religion. In the past, identity was often very local and concrete, expressed through friendship groups, churches, or clubs. To feel that one is part of a nation requires a big imaginative leap, and national consciousness has often been sharpened, or even generated, by fear of a hostile “Other” against which to counterpose one’s own nation and its values. But nationalism also needs expression in a political structure—a state—in order to gain the legal and emotional leverage over people that is necessary to shape the sense of national identity. In 1800, Europe comprised some five hundred political units, varying hugely in size and viability; by 1900 there were only about twenty. During the nineteenth century, states were forged largely by people’s wars, fought in the name of the nation and involving mass armies raised by conscription, for which the prototype was France during the Revolution and the Napoleonic Empire. France’s wars aroused national consciousness elsewhere, especially in the lands that became Italy and Germany. To quote Thomas Nipperdey’s history of modern Germany, “in the beginning was Napoleon.”

From these nineteenth-century struggles scholars developed a distinction between a civic nation and an ethnic nation. The former signified a community of laws, institutions, and citizenship within a defined territory, whereas an ethnic nation was defined as a community of shared descent, rooted in language, ethnicity, and culture. France was seen as the embodiment of civic nationalism, forged by the ideology of the Revolution (liberté, egalité, fraternité), Germany as the classic example of ethnic nationalism, steeped in Romantic conceptions of the Volk. This stark contrast between civic and ethnic nations has been questioned by some recent scholars, yet the general distinction remains useful.