Radyně Castle, like the similarly conceived Kasperk, represents the height of the 14th-century trend towards the merging of castle buildings.
When the castle of Starý Plzenec fell into disrepair in the first half of the 13th century, it was necessary to build a new centre of royal power for the administration of the region of Plzeň. Construction apparently began in 1353, during the rule of Charles IV, and was completed in 1361. The original name of Karlskrone (Charles' Crown) did not become commonly used in the district, and the castle gradually took the name of the hill on which it was built - Radyně.
The burgraves who governed the region were based in Radyně, and by the end of the 15th century it had been acquired by the Šternberks (1496–1561), who settled at the more comfortable castle at Bechyně. Its counterpart at Radyně, which was accessible only with difficulty, started to fall into disrepair, and its fate was sealed in the first quarter of the 16th century when it was burned down. As early as 1558, record indicated that it was abandoned, and not even the affluent Černín of the Crudenice family, owners of the castle as well as the surrounding district in the 18th century, invested in repair work. The mysterious abandoned ruin had to wait until the coming of the Romantic movement in the 19th century for more interest to be shown in it. Minor repairs and alterations were however destroyed by fire in 1886.
In recent years, the castle has been progressively renovated, and a permanent exhibition devoted to its history can now be seen. The tower is open to visitors of the castle, and its observation point affords wonderful views.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.