Rosenburg castle is one of Austria's most visited Renaissance castles. It is situated in the middle of a nature reserve which adds to its appeal. The Rosenburg was mentioned in a document for the first time in 1175, in relation to the area of the border along the Kamp River between Poigreich and the Babenberg settlements with the centres, the Benedictine Altenburg Abbey and the Gars-Thunau castle complex.
The Grabner brothers acquired the Rosenburg in 1487. From 1593–97, under the rule and by order of Sebastian Grabner, a Lutheran, most of the Gothic Rosenburg was demolished and the castle was reconstructed in Renaissance style with 13 towers. The Rosenburg remained in the possession of the Grabner family until 1604.
Finally, the Rosenburg became the property of the House of Sprinzenstein. A period of neglect followed, then several tragedies struck. Lightning caused a fire in 1721, and another fire broke out in 1751 which destroyed part of the courtyard gate and the chapel. In 1800, another fire damaged the Rosenburg; it was barely used for some 60 years thereafter. Fortunately, the Romantic Era caused a renewed interest in castles, and the castle was renovated by Count Ernst Carl von Hoyos-Sprinzenstein senior rebuilt the castle at great personal expense between 1859 and 1889. The castle is now a museum.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.