Holstein-Glückstadt

Holstein-Glückstadt or Schleswig-Holstein-Glückstadt is the historiographical name, as well as contemporary shorthand name, for the parts of the duchies of Schleswig and Holstein that were ruled by the Kings of Denmark in their function as dukes of Schleswig and Holstein, thus also known as Royal Schleswig-Holstein. Other parts of the duchies were ruled by the Dukes of Schleswig-Holstein-Gottorp. The territories of Holstein-Glückstadt are located in present-day Denmark and Germany. The main centre of administration was Segeberg and from 1648 Glückstadt (founded in 1617) on the River Elbe.

After the death of Frederick I of Denmark - who was also Duke of Schleswig and Holstein - his three sons partitioned the Duchies between them in 1544 whereby each of the three brothers received a part of both duchies:

In addition, significant parts of Holstein were jointly administered by the Dukes of Holstein-Glückstadt and the Dukes of Holstein-Gottorp, mainly on the Baltic Sea coast.

In 1640, the County of Holstein-Pinneberg, whose ruling house was extinct, was merged into the royal part of the Duchy of Holstein.

In 1713, the estates of the Dukes of Schleswig-Holstein-Gottorp in Schleswig including Schloss Gottorf were conquered by royal Danish troops in the course of the Great Northern War and in the 1720 Treaty of Frederiksborg, Duke Charles Frederick of Schleswig-Holstein-Gottorp had to cede them to his liege lord the Danish crown.

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