Brandenburg–Prussia (German: Brandenburg-Preußen; Low German: Brannenborg-Preußen) is the historiographic denomination for the early modern realm of the Brandenburgian Royal dynasty of the House of Hohenzollern between 1618 and 1701. Based in the Electorate of Brandenburg, the main branch of the Hohenzollern intermarried with the branch ruling the Duchy of Prussia, and secured succession upon the latter's extinction in the male line in 1618.
Another consequence of the intermarriage between the nobility was the acquisition / incorporation of the lands far to the west of Brandenburg–Prussia located in western Germany of the Holy Roman Empire (A.D. c. 800 / 962 to 1806), and situated in the lower Rhenish / Rhine River of the principalities of the Duchy of Cleves, County of Mark and County of Ravensberg after the signing and agreements in the Treaty of Xanten in 1614.