Bourglinster castle is first mentioned in 1098 as belonging to St Symeon of Trier. At the time it had a residential keep, a chapel and a wall. During the second half of the 14th century, the chapel was extended and a tower was added on the northern side. The lower castle with a moat and two defensive towers was built in the 15th century. Both castles were partly destroyed during the 16th century wars (1542–1544) but were soon repaired and a Renaissance wing was added (1548).
Parts of the lower castle were again destroyed by the French in the 1680s. In the early 18th century, a Baroque façade was built at the far end of the courtyard. After the castle was acquired by the Luxembourg State in 1968, the buildings were fully restored and, in 1982, opened for exhibitions, concerts, meetings and receptions.
The castle' s three banqueting halls with facilities for up to 200 people offer venues for business meetings, gala dinners and cultural events. La Distillerie, a restaurant on the castle premises, is considered to be one of the best in Luxembourg.
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.