Schleswig-Holstein-Sonderburg-Plön

The scattered territorial dominion lay mostly in the southeast part of present-day German state of Schleswig-Holstein.

In addition to the creation of Schleswig-Holstein-Plön, the import of this will and testament was that four other small duchies were formed as part of the physical division of Schleswig-Holstein.

In 1669 the Duchy of Schleswig-Holstein-Plön was given the land of another ducal sub-division, that of Schleswig-Holstein-Sonderburg-Norburg, consisting of the northern part of the island of Als.

The proceedings dragged on for many years and on 24 May 1729, the Duke of Rethwisch died without an heir, whereupon Plön then went to the son of Charles Christian.

This happened for both economic reasons – the royal house had enough residences on the mainland – as well as for political reasons, because it enabled Denmark to signal an abrupt end to the territorial fragmentation of Schleswig-Holstein, something which was finally sealed by the Treaty of Tsarskoe Selo and the emergence of the Greater Denmark state.

In the mid-18th century, it largely consisted of the following administrative units, some of which are identical with the present-day towns and villages of the same name: From 1623 to 1636 the ducal residence was located in Ahrensbök in Hoppenbrook Castle on the site of the former buildings of the Carthusian monastery.