The Tolštejn Castle (now reduced to ruins) was built in 1278 as part of the Zittau region's defense structure. George of Poděbrady ordered the castle to be seized shortly after the Hussite Wars and after many conflicts, the Tolštejn dominion was taken by 1471 by two Saxon princes, Ernest and Albrecht. During the Thirty Years War, the army of the Austrian Emperor occupied the castle. In 1607, the Swedish General Wrangel laid siege and burned down the castle.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.