Arnsberg

Arnsberg grew beneath a castle above a bend of the Ruhr in the wooded Sauerland. It was the seat of the counts of Arnsberg and had town rights by 1238. The castle dominated the old town and served as the centre of a small county contested by its powerful neighbours.

In 1368 the childless Count Gottfried IV transferred his county to the archbishop of Cologne, helping to consolidate Cologne's Duchy of Westphalia. Arnsberg Castle later served the electors of Cologne as a residence and, during the Soest Feud of 1444–1449, as their military headquarters during the conflict. The castle was destroyed by artillery fire in 1762 during the Seven Years' War; the town remained an important administrative centre after its fortress had fallen into ruin.