Plön

Plön lies on a narrow strip of land between lakes and the river Schwentine. Slavic inhabitants built a stronghold on an island in the lake, and after its destruction in 1139 the counts of Holstein established a castle on the wooded hill above the later town. A market settlement grew beneath it on the road north from Lübeck and received Lübeck town law in 1236.

The partition of the Danish royal family's lands created the duchy of Schleswig-Holstein-Plön in 1622. Duke Joachim Ernest rebuilt the castle as a Renaissance residence between 1633 and 1636, making Plön the seat of his small principality. In 1685 Duke John Adolphus founded a new town for craftsmen. The ducal line ended in 1761, when its lands returned to the Danish crown.