The concept of Germany as a distinct region in central Europe can be traced to Roman commander Julius Caesar, who referred to the unconquered area east of the Rhine as Germania, thus distinguishing it from Gaul , which he had conquered. The victory of the Germanic tribes in the Battle of the Teutoburg Forest prevented annexation by the Roman Empire, although the Roman provinces of Germania Superior and Germania Inferior were established along the Rhine. Following the Fall of the Western Roman Empire, the Franks conquered the other West Germanic tribes. When the Frankish Empire was divided among Charles the Great's heirs in 843, the eastern part became East Francia. In 962, Otto I became the first Holy Roman Emperor of the Holy Roman Empire, the medieval German state.

In the Late Middle Ages, the regional dukes, princes, and bishops gained power at the expense of the emperors. Martin Luther led the Protestant Reformation within the Catholic Church after 1517, as the northern states became Protestant, while the southern states remained Catholic. The two parts of the Holy Roman Empire clashed in the Thirty Years' War , which was ruinous to the twenty million civilians living in both parts. The Thirty Years' War brought tremendous destruction to Germany; more than 1/4 of the population and 1/2 of the male population in the German states were killed by the catastrophic war. The estates of the Holy Roman Empire attained an high extent of autonomy in the Peace of Westphalia, some of them being capable of their own foreign policies or controlling land outside of the Empire, the most important being Austria, Prussia, Bavaria or Saxony. With the French Revolution and the Napoleonic Wars from 1803 to 1815, feudalism fell away by reforms and the dissolution of the Holy Roman Empire. Thereafter liberalism and nationalism clashed with reaction. The German revolutions of 1848–49 failed. The Industrial Revolution modernized the German economy, led to the rapid growth of cities and the emergence of the socialist movement in Germany. Prussia, with its capital Berlin, grew in power. German universities became world-class centers for science and humanities, while music and art flourished. The unification of Germany was achieved under the leadership of the Chancellor Otto von Bismarck with the formation of the German Empire in 1871. This resulted in the Kleindeutsche Lösung, , rather than the Großdeutsche Lösung, . The new Reichstag, an elected parliament, had only a limited role in the imperial government. Germany joined the other powers in colonial expansion in Africa and the Pacific.