Iron: The mining of iron was often protected by castles in the Middle Ages.

Iron:
At a time when wood and clay were the main materials from which everyday objects were made, iron, along with copper, tin and bronze, was a particularly popular material. Many mining sites where the iron ore was also smelted in racing furnaces were protected by castles nearby. As here in the Brexbachtal, a side valley to the Middle Rhine, iron mining and smelting was protected by the ancestral castle of the Sayner lords. Erected by the Counts of Sayn around 1100, the complex extended over a length of approx 220 m and consisted of three parts, a main hill with a mothballed residential tower, then a little lower down a building and a well, and finally something on top of another lower hill another slightly smaller residential tower. The remains of several iron smelting plants were found in the valley below the castle.