section_path: History/Modern states
section_name: Modern states
paragraph_text: Modern states
  
  The Peace of Westphalia (1648) is considered by political scientists to be the beginning of the modern international system, in which external powers should avoid interfering in another country's domestic affairs. The principle of non-interference in other countries' domestic affairs was laid out in the mid-18th century by Swiss jurist Emer de Vattel. States became the primary institutional agents in an interstate system of relations. The Peace of Westphalia is said to have ended attempts to impose supranational authority on European states. The "Westphalian" doctrine of states as independent agents was bolstered by the rise in 19th century thought of nationalism, under which legitimate states were assumed to correspond to nations —groups of people united by language and culture.
  
  In Europe, during the 18th century, the classic non-national states were the multinational empires: the Austrian Empire, Kingdom of France, Kingdom of Hungary, the Russian Empire, the Spanish Empire, the Ottoman Empire, and the British Empire. Such empires also existed in Asia, Africa, and the Americas; in the Muslim world, immediately after the death of Muhammad in 632, Caliphates were established, which developed into multi-ethnic transnational empires. The multinational empire was an absolute monarchy ruled by a king, emperor or sultan. The population belonged to many ethnic groups, and they spoke many languages. The empire was dominated by one ethnic group, and their language was usually the language of public administration. The ruling dynasty was usually, but not always, from that group. Some of the smaller European states were not so ethnically diverse, but were also dynastic states, ruled by a royal house. A few of the smaller states survived, such as the independent principalities of Liechtenstein, Andorra, Monaco, and the republic of San Marino.
  
  Most theories see the nation state as a 19th-century European phenomenon, facilitated by developments such as state-mandated education, mass literacy, and mass media. However, historians also note the early emergence of a relatively unified state and identity in Portugal and the Dutch Republic. Scholars such as Steven Weber, David Woodward, Michel Foucault, and Jeremy Black have advanced the hypothesis that the nation state did not arise out of political ingenuity or an unknown undetermined source, nor was it an accident of history or political invention. Rather, the nation state is an inadvertent byproduct of 15th-century intellectual discoveries in political economy, capitalism, mercantilism, political geography, and geography combined with cartography and advances in map-making technologies.
  
  Some nation states, such as Germany and Italy, came into existence at least partly as a result of political campaigns by nationalists, during the 19th century. In both cases, the territory was previously divided among other states, some of them very small. Liberal ideas of free trade played a role in German unification, which was preceded by a customs union, the Zollverein. National self-determination was a key aspect of United States President Woodrow Wilson 's Fourteen Points, leading to the dissolution of the Austro-Hungarian Empire and the Ottoman Empire after the First World War, while the Russian Empire became the Soviet Union after the Russian Civil War. Decolonization lead to the creation of new nation states in place of multinational empires in the Third World.