Eutin Castle was originally a four-winged palace originating from a medieval castle and was expanded over several centuries into a residence. The castle originally belonged to the Lübeck prince-bishops, later it became the summer residence of the Dukes of Oldenburg. The castle was regularly occupied until the 20th century and most of the interior has survived to the present-day. Today the castle houses a museum and is open to the public in summer. It is now owned by a family foundation headed by Anton-Günther, Duke of Oldenburg. The former Baroque garden was converted during the 18th and 19th century to a landscaped park; this is the venue for the Eutin festivals.
A small, late Baroque hunting lodge on the Ukleisee belongs to Eutin Castle. The lodge was built in 1776 at some distance from the main castle at the behest of Frederick Augustus I of Saxony in order to provide a single-storey pavilion for hunting parties and guests attending special occasions.References:
First record of Kastelholma (or Kastelholm) castle is from the year 1388 in the contract of Queen Margaret I of Denmark, where a large portion of the inheritance of Bo Jonsson Grip was given to the queen. The heyday of the castle was in the 15th and 16th centuries when it was administrated by Danish and Swedish kings and stewards of the realms. Kastelhoma was expanded and enhanced several times.
In the end of 16th century castle was owned by the previous queen Catherine Jagellon (Stenbock), an enemy of the King of Sweden Eric XIV. King Eric conquered Kastelholma in 1599 and all defending officers were taken to Turku and executed. The castle was damaged under the siege and it took 30 years to renovate it.
In 1634 Åland was joined with the County of Åbo and Björneborg and Kastelholma lost its administrative status.