Duchy of Schleswig-Holstein-Sonderburg

Duchy of Schleswig-Holstein-Sonderburg-Plön

Duchy of Schleswig-Holstein-Sonderburg-Plön-Rethwisch

In 1565, the King of Denmark, in his roles as Duke of Schleswig and Duke of Holstein, spun off the nonsovereign Duchy of Schleswig-Holstein-Sonderburg for the benefit of his brother. Although Sonderburg was in Schleswig, the Duchy contained territory in Holstein, so I give it the simplified country name of Holstein-Sonderburg. (Schleswig itself was outside of the Holy Roman Empire and is not considered here in any detail.)

 

In 1623, following the death of the Duke of Sonderburg, the country splintered into five new duchies, four of which were entirely within Schleswig. The fifth started out entirely within Holstein, and I give it the simplified country name of Holstein-Plön. In 1671, another Duchy, which I give the simplified country name of Holstein-Rethwisch, was spun off from Plön. It consisted solely of the Amt of the same name and reverted to Plön in 1729. (In 1679, the Plön Duchy acquired Amt Norburg in Schleswig and immediately spun it off into a separate duchy. It reverted to Plön in 1706.) In 1761, the Plön line died out and its Holstein territory reverted to the core Duchy of Holstein. (The last of the Schleswig lands that had been assigned to Sonderburg reverted to the core Duchy of Schleswig in 1779.)