Neu-Montfort was a medieval hilltop castle in Götzis built between 1311-1319 by the Count of Montfort. 50 years later they sold their rule to the Habsburgs, who were able to acquire in 1363 the first piece of Vorarlberg. Neu-Montfort is one of the few castles that were not destroyed by the Appenzell Wars (1405-1408). The decline began in 1693 when the last resident Ulrich Koch died.
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.