Unification of Germany

The formal unification of Germany into a politically and administratively integrated nation state officially occurred on 18 January 1871 at the Versailles Palace's Hall of Mirrors in France. Princes of the German states gathered there to proclaim Wilhelm of Prussia as Emperor Wilhelm of the German Empire after the French capitulation in the Franco-Prussian War. Unofficially, the transition of most of the German-speaking populations into a federated organization of states occurred over nearly a century of experimentation. Unification exposed several glaring religious, linguistic, social, and cultural differences between and among the inhabitants of the new nation, suggesting that 1871 only represents one moment in a continuum of the larger unification processes.

The Holy Roman Empire of the German Nation, which had included more than 300 independent states, was effectively dissolved when Emperor Francis II abdicated (6 August 1806) during the War of the Third Coalition. Despite the legal, administrative, and political disruption associated with the end of the Empire, the people of the German-speaking areas of the old Empire had a common linguistic, cultural and legal tradition further enhanced by their shared experience in the French Revolutionary Wars and Napoleonic Wars. European liberalism offered an intellectual basis for unification by challenging dynastic and absolutist models of social and political organization; its German manifestation emphasized the importance of tradition, education, and linguistic unity of peoples in a geographic region. Economically, the creation of the Prussian Zollverein (customs union) in 1818, and its subsequent expansion to include other states of the German Confederation, reduced competition between and within states. Emerging modes of transportation facilitated business and recreational travel, leading to contact and sometimes conflict between and among German-speakers from throughout Central Europe.

The model of diplomatic spheres of influence resulting from the Congress of Vienna in 1814–15 after the Napoleonic Wars endorsed Austrian dominance in Central Europe. However, the negotiators at Vienna took no account of Prussia's growing strength within and among the German states, failing to foresee that Prussia would challenge Austria for leadership within the German states. This German dualism presented two solutions to the problem of unification: Kleindeutsche Lösung, the small Germany solution (Germany without Austria), or Großdeutsche Lösung, greater Germany solution (Germany with Austria).

Historians debate whether or not Otto von Bismarck, the Minister President of Prussia, had a master plan to expand the North German Confederation of 1866 to include the remaining independent German states into a single entity, or whether he simply sought to expand the power of the Kingdom of Prussia. They conclude that factors in addition to the strength of Bismarck's Realpolitik led a collection of early modern polities to reorganize political, economic, military and diplomatic relationships in the 19th century. Reaction to Danish and French nationalism provided foci for expressions of German unity. Military successes—especially Prussian ones—in three regional wars generated enthusiasm and pride that politicians could harness to promote unification. This experience echoed the memory of mutual accomplishment in the Napoleonic Wars, particularly in the War of Liberation of 1813–14. By establishing a Germany without Austria, the political and administrative unification in 1871 at least temporarily solved the problem of dualism.