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 (France), which he had conquered. The victory of the Germanic tribes in the Battle of the Teutoburg Forest (AD 9) prevented annexation by the Roman Empire. Following the fall of the Roman Empire, the Franks conquered the other West Germanic tribes. When the Frankish Empire was divided among Charlemagne's heirs in 843, the eastern part became East Francia. In 962, Otto I became the first emperor of the Holy Roman Empire, the medieval German state.
In the High Middle Ages, the dukes and princes of the empire gained power at the expense of the emperors. Martin Luther led the Protestant Reformation against the Catholic Church after 1517, as the northern states became Protestant, while the southern states remained Catholic. They clashed in the Thirty Years' War (1618–1648), which was ruinous to the twenty million civilians. 1648 marked the effective end of the Holy Roman Empire and the beginning of the modern nation-state system, with Germany divided into numerous independent states, such as Prussia, Bavaria and Saxony.
Germany (i/ˈdʒɜrməni/), officially the Federal Republic of Germany (German: Bundesrepublik Deutschland, pronounced [ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant] ( listen)), is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate. With 81.8 million inhabitants, it is the most populous member state and the largest economy in the European Union. It is one of the major political powers of the European continent and a technological leader in many fields.
A region named Germania, inhabited by several Germanic peoples, was documented before AD 100. During the Migration Period, the Germanic tribes expanded southward, and established successor kingdoms throughout much of Europe. Beginning in the 10th century, German territories formed a central part of the Holy Roman Empire. During the 16th century, northern German regions became the centre of the Protestant Reformation while southern and western parts remained dominated by Roman Catholic denominations, with the two factions clashing in the Thirty Years' War, marking the beginning of the Catholic–Protestant divide that has characterized German society ever since. Occupied during the Napoleonic Wars, the rise of Pan-Germanism inside the German Confederation resulted in the unification of most of the German states into the German Empire in 1871 which was Prussian dominated. After the German Revolution of 1918–1919 and the subsequent military surrender in World War I, the Empire was replaced by the Weimar Republic in 1918, and partitioned in the Treaty of Versailles. Amidst the Great Depression, the Third Reich was proclaimed in 1933. The latter period was marked by Fascism and World War II. After 1945, Germany was divided by allied occupation, and evolved into two states, East Germany and West Germany. In 1990 Germany was reunified.