Kumna manor, founded in the 1620s, has belonged to the Knopiuses, Lübkens, von Koskülls and also to the von Meyendorffs. The wooden main building dating from the 18th century was reconstructed in the 19th century (was used as apartments, currently dilapidated). The new two-storey Neo-Classical main building (built in 1913-1920) is in private possession and is being restored.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.