Bear, another Saxon count from the noble House of Ascania, who established the Margraviate of Brandenburg in 1157. His son Margrave Otto I already achieved the dignity of an Arch-Chamberlain of the Holy Roman Empire in 1177. Emperor Charles IV by the Golden Bull of 1356 confirmed the electoral dignity of the Brandenburg margraves and in 1373 assigned the electorate to his son Wenceslaus in 1373. The Elector of Brandenburg held the seventh rank among the electors of the Empire and had five votes in the Council of Princes. In 1415 Brandenburg was acquired by Burgrave Frederick of Nuremberg, the first member of the Swabian House of Hohenzollern to rule the margraviate. Over the centuries, the Hohenzollerns gradually rose to one of the most important dynasties of the Empire, rivalling with the ruling House of Habsburg, a process that intensified with the Protestant Reformation and the inheritance of the Polish Duchy of Prussia in 1618. The margraviate formed the core of the Brandenburg-Prussian state and the "Great Elector" Frederick William I made various accessions to the territory, the Treaty of Königsberg of 1656 marking a significant turn in its evolution. By the 1657 Treaty of Wehlau, Frederick William reached full sovereignty in his Prussian territories, which enabled his son Frederick I to assume the crown of a "King in Prussia" in 1701. Establishment The margraviate remained a constituent part of Prussia, until after the Napoleonic Wars and the 1815 Congress of Vienna the kingdom's administration was divided into ten provinces. Most of the Margraviate's territory was incorporated into the new Province of Brandenburg, most notably the Mittelmark between the rivers Elbe and Oder and the Neumark region east of the Oder River. However, the Altmark on the western bank of the Elbe was incorporated into the Prussian Province of Saxony. The Province of Brandenburg also encompassed the territory of Lower Lusatia (where Cottbus had been a Brandenburgian exclave since the 15th century) as well as the area around Belzig and Jüterbog, all annexed from the Kingdom of Saxony for her alliance with Napoleon. The Province headed by an Oberpräsident was subdivided into two governorates (Regierungsbezirke) named after their respective capitals, Potsdam in the northwest (Mittelmark, Prignitz and Uckermark) and Frankfurt (Oder) in the southeast (Neumark and Lower Lusatia). The provincial government was at first situated at the Potsdam royal residence. In 1827, it moved to Berlin, returned to Potsdam in