First documented in the 13th century and at the crossing of two important historic trade routes, Berlin became the capital of the Margraviate of Brandenburg (14171701), the Kingdom of Prussia (1701–1918), the German Empire (1871–1918), the Weimar Republic (1919–1933), and the Third Reich (1933–1945). Berlin in the 1920s was the third-largest municipality in the world. After World War II and its subsequent occupation by the victorious countries, the city was divided; West Berlin became a de facto exclave of West Germany, surrounded by the Berlin Wall (1961–1989) and East German territory. East Berlin was declared capital of East Germany, while Bonn became the West German capital. Following German reunification in 1990, Berlin once again became the capital of all of Germany.