Zwingenberg Castle dates from the 13th century. In the 1326 the lords of Zwingenberg were mentioned as an owner. In 1364 the castle was conquered and destroyed by the imperial forces. The fortress and estate were then immediately divided in two equal parts and bought by the Palatinate and the archbishoprie of Mainz. The reconstruction of the castle was made by the brothers Hans and Eberhard of Hirschhorn in 1404. The brothers were invested with the castle by Mainz and the Palatinate. We owe the building as it appears today essentially to them.
In 1778 Karl Theodor of the Palatinate conferred it upon his natural son the count of Bretzenheim; the count’s mother the countess of Heydeck, was buried in the castle chapel, where her tomb still stands today.
in 1808 the palatinate was divided up upon Napoleons orders the new sovereign the Grand Duke Karl Friedrich of Baden purchased it with his own private means. Since then it has been family property of the house of Baden.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.