Some of the smaller European states were not so ethnically diverse, but were also dynastic states, ruled by a royal house. Their territory could expand by royal intermarriage or merge with another state when the dynasty merged. In some parts of Europe, notably Germany, very small territorial units existed. They were recognized by their neighbors as independent, and had their own government and laws. Some were ruled by princes or other hereditary rulers, some were governed by bishops or abbots. Because they were so small, however, they had no separate language or culture: the inhabitants shared the language of the surrounding region.
In some cases these states were simply overthrown by nationalist uprisings in the 19th century. Liberal ideas of free trade played a role in German unification, which was preceded by a customs union, the Zollverein. However, the Austro-Prussian War, and the German alliances in the Franco-Prussian War, were decisive in the unification. The Austro-Hungarian Empire and the Ottoman Empire broke up after the First World War, and the Russian Empire became the Soviet Union after the Russian Civil War.
