Italy and Germany's union was primarily motivated by nationalism. This philosophy, which was formed during the French Revolution and the Napoleonic Invasion period, was a major aspect of Europe in the 19th century. Nationalism brought people of the same nationality together in a single, unified political entity since it was based on the premise that each nation—those who shared a common language, history, customs, etc.—should have its own State. After three wars, Germany established a single state that continued to be governed by the former Kingdom of Prussia. Nationalism would also act as a destabilizing force, though, as it was a major factor in various wars, including the above-mentioned independence wars, that broke out during the XIX Century. Furthermore, it would exert both a centripetal and a centrifugal effect on the political geography of Europe: numerous multinational empires would experience ongoing crises and uprisings led by various national minorities who want to establish their own nation-state. Additionally, one of the primary reasons for the First World War is said to have been nationalism and the nationalist ideal. Nationalism was also connected to more radical political ideologies like the segregation of minorities and institutionalized racism.