The original structure of Scharfenstein castle was built in 1250. It is suspected that the von Waldenburgs ordered its construction, but only its first owner occupant is known for certain. When, in the 15th century, Greifenstein Castle was destroyed, Scharfenstein also took over the guardianship of Thum, Ehrenfriedersdorf and Geyer. As a result, its value increased, so that in 1439 the Elector acquired the area from the Waldenburgs who were heavily indebted to him. On 26 January 1492 Henry of Einsiedel bought Scharfenstein Castle and its associated villages of Grießbach, Großolbersdorf, Grünau, Hohndorf Hopfgarten and Scharfenstein It remained in the family until 1931.
Following a fire during the night of 1st-2nd June 1921 the entire residential wing and part of the domestic wing was destroyed. From 1921 to 1923 the damaged wings were partially rebuilt to plans by Bodo Ebhardt, based on the old design.
In 1931, a factory owner, Captain Eulitz from Fährbrücke, acquires possession. By his efforts in 1932 in a bird observatory was established. Hundreds of nest boxes were put up throughout the 325 hectares of woodland on the estate; bird-ringing was carried out and scientific reports published, with the support of the Chemnitz Ornithological Society.
In 1945 this forest was seized and made public property, the castle was initially used as the mining school for the state-owned Wismut mining company and, in 1951, a special children's home was established here for maladjusted boys. In 1967, it was converted into a detention centre for juvenile delinquents. Ornithological work was undertaken by the museum at Augustusburg Castle.
In 1993 the castle was taken over by the Saxon Palace Department of the Free State of Saxony. In the period that followed the castle was renovated as a historic monument and converted into a museum. In 1995, on the completion of the renovation work, various exhibitions were opened - and for the first time since 1945, the castle was again open to the public. The bergfried is still used today as an observation tower.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.