The Province of Brandenburg () was a province of Prussia from 1815 to 1945. Brandenburg was established in 1815 from the Kingdom of Prussia's core territory, comprised the bulk of the historic Margraviate of Brandenburg (excluding Altmark) and the Lower Lusatia region, and became part of the German Empire in 1871. From 1918, Brandenburg was a province of the Free State of Prussia until it was dissolved in 1945 after World War II, and replaced with reduced territory as the State of Brandenburg in East Germany, which was later dissolved in 1952. Following the reunification of Germany in 1990, Brandenburg was re-established as a federal state of Germany, becoming one of the new states. Brandenburg's provincial capital alternated between Potsdam, Berlin, and Charlottenburg during its existence. Geography The province comprised large parts of the North German Plain, stretching from the Elbe river in the west to beyond the Oder in the east, where the Neumark region bordered on the Prussian Grand Duchy of Posen (Province of Posen from 1848). Other neighbouring provinces were Pomerania in the northeast, Silesia in the southeast, and Prussian Saxony in the southwest. Brandenburg also shared a common border with the grand duchies of Mecklenburg-Schwerin and Mecklenburg-Strelitz in the northwest as well as with Anhalt in the west. Beside the Elbe and Oder river areas, the province covered large parts of the Spree and Havel basin. The largest cities were Berlin, located in the centre together with the growing suburbs of Spandau, Charlottenburg, Schöneberg and Neukölln. Larger towns were the royal residence Potsdam and the regional capital Frankfurt (Oder), furthermore Landsberg (present-day Gorzów Wielkopolski) in the east, the historic capital Brandenburg an der Havel as well as Cottbus, Forst and Guben (Gubin) in Lower Lusatia. History The first people who are known to have inhabited Brandenburg were the Germanic Suebi. During the Migration Period, they were succeeded by the Polabian Slavs, whose fortress at Brandenburg an der Havel was conquered by the German king Henry the Fowler in 928/29. Henry subdued the Slavic tribes up to the Oder river and his son Otto I established the marca Geronis on their territory, with the government first conferred to the Saxon count Gero. The Northern March was split off in 965, however, large parts were again lost in the Great Slav Rising of 983, and the margravial title did not become hereditary until the time of Albert the