There was a small fort in Bettembourg as far back as the 10th century. A tower was added later but was removed when further extensions were made in the 17th century. A second castle was built around 1733 by Lothaire de Zievel and his wife Appolinaire-Agnès-Elisabeth de Haagen Motten. The neighbouring stream known as the Düdelingerbach was probably one of the reasons they chose the site. The rather austere architectural style was typical of the period, especially as the building was designed in the interests of farming.
The oldest part of the castle is the south wing which housed stables and barns. The north wing, now the main part of the U-shaped complex, was added later. In about 1759, Jean-Henri de Zievel charged the architect Rousselet de Boulay with major restoration work. In 1765, on the death of the last member of the De Zievel family, the castle fell into the hands of the castle manager, Marc-Antoine de Verniolles. Various proprietors followed including members of the Hohenzollern-Hechingen-Haigerloch family (1780), Charles Joseph Collart de Donnea, owner of the Dommeldange iron works (1807), followed by various members of the Collart family until 1971. When his wife, Daisy Collart-Weber, died in 1969, August Collart decided to sell the property. The commune of Bettembourg bought the property in 1971 and, after undertaking extensive restoration and reconstruction work, opened the building as the Bettembourg town hall in 1991.
The castle now serves as the commune's administrative building and as the town hall of Bettembourg. One of the important transformations has been the creation of a large cultural room or art gallery. The castle's ornamental wooden panelling and its many fireplaces are of particular interest. The large park surrounding the castle is also open to the public.
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.