Karlsruhe was one of the new cities built on a geometric plan during the 18C by the builder princes of southern Germany. The castle of the Margrave of Bade-Durlach was designed in 1715 as the focal point of a fan-shaped town: Karlsruhe. The city came into its own during the 19C when it was made the capital of the Grand Duchy of Bade (1806). Today, it is the seat of the Federal Republic supreme courts. Its university is the oldest technical college in Germany (1825).