Schleswig-Holstein-Sonderburg
Schleswig-Holstein-Sonderburg was the name of a branch line of the House of Oldenburg as well as the name of their land. It existed from 1564 until 1668 and was a titular duchy under the King of Denmark, rather than a true territorial dukedom in its own right. The seat of the duke was Sønderborg. Parts of the domain were located in Denmark, mainly on the islands of Als and Ærø and around Glücksburg, whilst other lands were part of the Holy Roman Empire, including the Ämter of Plön, Ahrensbök, and Reinfeld. As a result of various inheritance arrangements it fragmented into numerous small territories which were eventually absorbed into Greater Denmark in the 18th century.
Coat of arms of the Dukes of Schleswig-Holstein-Sonderburg
The Duchy of Schleswig-Holstein-Sonderburg was founded by John III and fragmented after his death into numerous mini-states
The House of Oldenburg is an ancient dynasty of German origin whose members rule or have ruled in Denmark, Iceland, Greece, Norway, Russia, Sweden, the United Kingdom, Livonia, Schleswig, Holstein, and Oldenburg. The current King of the United Kingdom and King of Norway are agnatic members of this house, meanwhile the King of Spain and King of Denmark are matrilineal members.
Oldenburg Palace in Oldenburg
Coat of arms of the counts of Oldenburg at Oldenburg Palace: red stripes on gold for Oldenburg; golden cross on blue for Delmenhorst
The first Oldenburg king was Christian I of Denmark, Norway and Sweden (1426–1481)
King Charles III of the United Kingdom (*1948)