Löwenburg castle was built around 1200 by the Counts of Sayn. Together with the Castle of Blankenberg high above the valley of river Sieg it secured their territory. In the second half of the 13th century the old keep was torn down. Only then the castle whose ruins we see today was built. In the late Middle Ages the Löwenburg went through an eventful history until it fell to the Counts of Berg in 1484. It was destroyed in the Thirty Years War.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.