Nordborg Castle

Nordborg Castle (Danish: Nordborg Slot) is a small castle which lies on the southern side of Nordborg Lake in Nordborg on the island of Als in Denmark. The castle premises are currently used as a boarding school.

Nordborg Castle was, according to Saxo, founded by Svend Grathe under the name Alsborg. Hence, it can be dated to around 1150.

Alsborg was built whilst the Wends still dominated the Danish coast; its location a few kilometers inland meant that the castle could not be attacked without warning, and the local population had a better chance of taking refuge there.

The first written evidence of Alsborg is from the end of the 12th century. From this it is known that Bishop Valdemar of Slesvig was held prisoner at Alsborg between 1192 and 1197.

After Sønderborg Castle was built, Alsborg was renamed Nordborg.

Nordborg was for a large part of the middle ages the property of the king, and was on several occasions a source of income for the king's widow.

In 1571 King Frederick II’s brother Hans the Younger inherited his mother Queen Dorothea's possessions of Als and Sundeved including Nordborg. Hans was an enterprising man, who in the next 50 years constantly expanded and improved his properties. There was a series of building projects in and around Nordborg Slot.

Upon Hans the Younger's death in 1622 his possessions were divided into separate dukedoms, including Nordborg, which went to his son Hans Adolf. Hans Adolf died only two years later and so the dukedom then went to Hans the Younger's other son Frederik.

...
Wikipedia