1843 and in 1918 finally settled in Charlottenburg. The Prussian capital Berlin originally formed part of the Province, but in the course of the Industrial Revolution from the 1830s onwards quickly developed to a metropolis, from 1871 as capital of the German Empire, and on 1 April 1881 was made an autonomous city district (Stadtkreis Berlin). In contrast, the rural outer regions, though serfdom had been officially abolished by the 1807 Prussian reforms, was still characterised by large–scale land holding of the Junker nobility, similar to the eastern Prussian provinces of Silesia and Pomerania. The conditions in the countryside remained largely untouched, even during the Revolutions of 1848 that led to violent fights in the streets of Berlin. The large estates had to deal with low soil quality and—except for brown coal occurrences in Lower Lusatia—the lack of natural resources. The provincial life was perpetuated in the novels by Theodor Fontane and especially in his 1862–89 descriptive work Wanderungen durch die Mark Brandenburg. Free State of Prussia After World War I and the resolutions of the 1919 Treaty of Versailles, the Province of Brandenburg shifted to the eastern edge of the German Weimar Republic, sharing a long common border with the Second Polish Republic. In 1920, the Greater Berlin Act expanded the borders of Berlin, incorporating numerous surrounding districts and towns from Brandenburg to form Greater Berlin (Groß-Berlin) with a population of about 2,000,000, including the former town of Charlottenburg, the seat of Brandenburg's provincial government. The Great Depression helped the Nazi Party to establish itself as an important political power. After the Machtergreifung on 30 January 1933, the Nazi Gauleiter Wilhelm Kube held the office of the Oberpräsident, succeeded by Emil Stürtz in 1936. Due to its location in the vicinity of the German capital, Brandenburg was a centre of the Nazi terror regime, with concentration camps like Sachsenhausen and Ravensbrück and Nazi residences like Karinhall. In the late days of World War II it was the site of the bloody encounters of the Seelow Heights, at Halbe and finally the Battle of Berlin. In 1945, after the war, the Neumark territory east of the Oder–Neisse line was ceded to the Republic of Poland to form the Zielona Gora Voivodeship (initially part of Poznan Voivodeship between 1945 and 1950, became Lubusz Voivodeship in 1998 after merging with Gorzów Voivodeship). The remaining territory became part of the Soviet occupation zone