Although the town of Brandenburg is less known than the state of Brandenburg, the state was named after the town and not vice versa. Today it is a small town, but once it was the origin of the realms of Brandenburg and Prussia.
The castle of Brandenburg, which had been a Slavic fortress, was conquered in 929 by king Henry the Fowler. The town remained German only until 983, when a Slavic rebellion was successful. In the next 170 years the area was ruled by Slavic princes of the Heveller tribe. The last of them, Pribislav, died in 1150. Afterwards Albert I settled here and became the first margrave of Brandenburg. The town was restricted to the western bank of the Havel until 1196, when it was extended to the eastern side. The parts on either side of the river were regarded as two different towns (Old and New Brandenburg) for centuries.
In 1314 (resp. 1315) the two towns joined the Hanseatic League. In the Thirty Years' War the towns suffered plundering and destruction; this led to a loss of power; the new capital became Potsdam, and the court left the town of Brandenburg. In 1715 the parts of the town were merged at last to a common town.