Maus Castle construction was begun in 1356 by Archbishop-Elector of Trier Bohemond II and was continued for the next 30 years by successive Electors of Trier. The construction of Burg Maus was to enforce Trier's recently acquired Rhine River toll rights and to secure Trier's borders against the Counts of Katzenelnbogen (who had built Burg Katz and Burg Rheinfels). In the latter half of the 14th century Burg Maus was one of the residences of the Elector of Trier.
Unlike its two neighbouring castles, Burg Maus was never destroyed, though it fell into disrepair in the 16th and 17th centuries. Restoration of the castle was undertaken between 1900 and 1906 under the architect Wilhelm Gärtner with attention to historical detail.
The castle suffered further damage from shelling during World War II which has since been repaired. Today Burg Maus hosts an aviary that is home to falcons, owls and eagles, and flight demonstrations are staged for visitors from late March to early October.
The ward of the castles contains two residential buildings. The vulnerable side facing uphill is guarded by a round bergfried.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.