Edmundsburg spans over three floors and is cubic with a small, central dome. It can be spotted easily from about anywhere in the old town, especially the Salzburger Dom.
Abbot Edmund Sinnhuber of St. Peter′s Abbey built the Edmundsburg Castle in 1696 and it remained the property of the abbey until 1834. After that, it became the site of a well-known school for boys. Until 2008, the Edmundsburg Castle held some offices and a private library of a foundation.
In 2008, it was let on a long-term-lease to the University of Salzburg and extensively renovated.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.