Brandenburg is one of the sixteen federal-states of Germany. It lies in the east of the country and is one of the new federal states that were re-created in 1990 upon the reunification of the former West Germany and East Germany. The capital is Potsdam. Brandenburg surrounds but does not include the national capital and city-state of Berlin.
Originating in the medieval Northern March, the Margraviate of Brandenburg grew to become the core of the kingdom, later Free State of Prussia. The eastern third of historic Brandenburg (Ostbrandenburg/Neumark) was ceded to Poland in 1945.
Brandenburg was formally part of the Confederated Principalities of Europe, but did not follow Gustavus Adolphus into the Ostend War, an action Gustavus saw as a betrayal. When the CPoE was succeeded by the United States of Europe, Brandenburg strongly refused to join the newly created nation.
Brandenburg was absorbed into the USE in September of 1635, after George William and his family fled Berlin.