Friedrich Wilhelm I of Brandenburg.

Friedrich Wilhelm (Frederick William) of Brandenburg, Kurfürst of Brandenburg, Duke of Prussia (February 16, 1620 - April 29, 1688) of the House of Hohenzollern, was the Kurfürst (elector) of Brandenburg, from 1640 until his death. He is known as the "Großer Kurfürst" (Great Elector).

Friedrich Wilhelm was born, in Berlin, to Georg Wilhelm von Brandeburg and Elisabeth Charlotte von der Pfalz . His inheritance was a completely devastated Brandenburg and Prussia, where the Thirty Years War had ravished and decimated the land and the population greatly. His father Georg Wilhelm had to keep a delicate balancing act between the northern Protestant forces and the Imperial Catholic forces. Out of these meager beginnings the Great Elector managed to rebuild the country and to get free of the overlords by the treaties of Wehlau, Labiau and Oliva.

Friedrich Wilhelm is notable for raising an army of 40,000 soldiers, by 1678. He was an advocate of mercantilism, monopolies, subsidies, tariffs, and internal improvements. He agreed to exempt the nobility from taxes, in return they agreed to dissolve the Estates-General.

He simplified travel in the ancestral lands of Brandenburg and Prussia by connecting riverways with canals, a system, that was expanded by later Prussian architects, such as Georg Steenke and which is still functioning and in use today.

On 7 December 1646, at The Hague, he married Luise Henriette von Nassau (1627-1667), daughter of Frederick Henry of Orange-Nassau and Amalia of Solms-Braunfels. Their children were Wilhelm Heinrich (1648-1649), Karl (1655-1674), Friedrich III-I (1657-1713), Amalie (1656-1664), Heinrich (1664-1664), and Ludwig (1666-1687)

On 13 June 1668 at Groningen he married Sophie Dorothea of Holstein-Glücksburg, daughter of Philipp von Holstein-Sonderburg-Glücksburg and Sophie Hedwig of Saxe-Lauenburg.

Their children were Philipp Wilhelm (1669-1711), Marie Amalie (1670-1739), Albrecht Friedrich (1672-1731), Karl (1673-1695), Elisabeth Sofie (1674-1748), Dorothea (1675-1676), and Christian Ludwig (1677-1734).

See also: General War Commissariat