For most of history, people lived in empires, kingdoms, city-states and tribal confederations, and their loyalties ran to a ruler, a faith, a lord or a locality. The idea that the world should be divided into nations, each governing itself, is surprisingly recent. This level traces how it spread.
Westphalia and sovereignty (1648)
The Peace of Westphalia, a set of treaties signed in 1648, ended the Thirty Years' War, a devastating conflict in Central Europe fought partly over religion. It is often taken as the birth of the modern system of states, built on the principle of sovereign states supreme within their own territory, with other rulers expected not to interfere in their internal affairs. Historians add an important caution: its states were dynastic, and sovereignty developed gradually over the following centuries. Sovereignty in 1648 belonged to princes and kings, not to nations. The treaties set the stage for a world of states, but not yet for nationalism.
The French Revolution (1789)
The decisive change came with the French Revolution. The Declaration of the Rights of Man and of the Citizen of 1789 stated that “the principle of all sovereignty resides essentially in the nation”. Sovereignty was said to reside in the nation, not the king. The French people were recast as citizens who owned their state. The revolutionaries introduced mass conscription, a national flag and anthem, and campaigns to spread standard French in a country where many people spoke other languages. Napoleon's armies then carried these ideas across Europe and, by conquering other peoples, provoked national feeling against France, especially in the German lands.
Meanwhile German writers developed a cultural idea of the nation. Johann Gottfried Herder argued that each people has its own language and culture, each valuable in its own way, and Johann Gottlieb Fichte, in his Addresses to the German Nation (1808), called on Germans to unite around their language and culture.
Nineteenth-century nation-building
In Italy, the movement known as the Risorgimento (resurgence) joined idealists such as Giuseppe Mazzini, the diplomat and statesman Camillo di Cavour, and the soldier Giuseppe Garibaldi. Through wars, diplomacy and popular campaigns, the Kingdom of Italy was proclaimed in 1861, and Rome became its capital in 1871.
In Germany, unification came largely from above, led by Prussia after a series of wars. Under the Prussian minister Otto von Bismarck, Prussia defeated Denmark (1864), Austria (1866) and France (1870 to 1871), and the German Empire was proclaimed in January 1871. Greece, Belgium, Serbia, Romania and others also emerged as national states during the century.
Self-determination after the First World War
The First World War destroyed four empires: the German, Austro-Hungarian, Russian and Ottoman. Leaders including the American president Woodrow Wilson and the Russian revolutionary Vladimir Lenin championed the self-determination of peoples, and new states appeared, among them Poland, Czechoslovakia, Yugoslavia and the Baltic states. But Central and Eastern Europe was a patchwork of peoples, so mixed populations meant every new border created new minorities. Treaties to protect minorities were signed under the League of Nations, but they proved weak.
Decolonization
After the Second World War, nationalism became the language of anti-colonial movements in Asia and Africa. The UN Charter of 1945 referred to the self-determination of peoples. India and Pakistan became independent in 1947, Ghana in 1957, and seventeen African countries in 1960 alone. In 1960 the UN General Assembly declared that colonialism should be brought to a speedy end. Most new states largely kept the borders drawn by colonial powers, so many contained several ethnic and language groups, and building a shared national identity became a central task after independence. The United Nations grew from 51 founding members to more than 190 today, making the nation-state the near-universal form of political organization.
Worked example: drawing a border in Upper Silesia
After the First World War, the peace treaties had to decide many borders in regions where peoples were mixed. Upper Silesia, a coal-mining and industrial region claimed by both Germany and the newly restored Poland, shows how hard self-determination could be in practice.
The Allies decided to hold a plebiscite, a vote of the inhabitants, in March 1921. About 60 percent of the votes went to Germany and about 40 percent to Poland. But the result did not fall neatly into two zones. Towns often voted differently from the surrounding villages, and German and Polish majorities sat side by side across the map. Some people spoke a local dialect and felt ties to both sides, or chiefly to their region.
Tension turned into fighting between Polish insurgents and German paramilitary forces. The question was referred to the League of Nations, and in late 1921 the region was divided. Poland received a smaller share of the territory but much of the industrial heartland, while Germany kept the larger part. Neither side was satisfied, and each now had a minority on the other side of the line. A special agreement tried to protect minorities and keep the region's economy working across the new border.
The lesson is not that self-determination is meaningless. People did want a say in which state ruled them. But where populations are mixed, any border leaves some people as minorities, and the principle of one nation, one state cannot be fully realized. That is why protecting minorities, wherever the border falls, became as important as the border itself.