Nationalism is a political and ideological doctrine which asserts that a people sharing common characteristics such as language, history, culture, territory, and collective memories constitute a distinct community called a nation, and that this nation has the right to political self-determination. It emphasizes loyalty and devotion to the nation above other forms of allegiance such as dynasty, region, or religion. In modern Europe, nationalism emerged as a powerful force from the late eighteenth century onward, particularly after the French Revolution, which proclaimed the sovereignty of the people and the idea that political authority derives from the nation rather than from divine right or hereditary monarchies. The concept of the nation-state is closely linked to nationalism. A nation-state is a political entity in which the boundaries of the state coincide, as far as possible, with the boundaries of a single nation. It implies that a culturally homogeneous population is organized under a sovereign political authority. In practice, perfect correspondence between nation and state rarely existed in Europe, but the aspiration to align political borders with national identities became a central goal of nineteenth-century politics. The nation-state thus represents both a territorial unit and an imagined community whose members perceive themselves as belonging to a common national body. Nationalism in Europe during the mid-eighteenth to mid-twentieth centuries manifested itself in two major and seemingly contradictory ways: as a force of unification and as a force of separation. The same ideological principle—the right of a nation to self-government—could inspire the consolidation of fragmented territories into unified states or encourage the break-up of multinational empires into independent nations. The French Revolution marked a turning point in the development of modern nationalism. Revolutionary leaders mobilized citizens in the name