The Old Town of Visoki was a medieval royal castle town built during the 14th century on the top of the hill overlooking town of Visoko, Bosnia and Herzegovina. The first mention of the town was on 1 September 1355, in the charter 'in castro nosto Visoka vocatum' written by Tvrtko I of Bosnia while he was a young ban. The town was abandoned before 1503, because it is not mentioned in the Turkish-Hungarian treaty from the mentioned year. In 1626, Đorđić mentioned Visoki among abandoned towns.
The Old Town of Visoki is at the top of Visočica hill, 213 metres high. Its position provides an excellent view at the plains below. The entry to the castle is on the southwest side, with two lookout towers. Passing through the entry you enter to a part that is called Podvisoki, i.e. to the town that was quite small, measuring 60 by 25 metres, and has signs and remains of early medieval houses. The thickness of the castle town walls is about 2 metres. Its position provides an excellent view at the plains below bordered by mountains Romanija, Jahorina, Treskavica and Bjelašnica in the east and southeast, Bitovnja in the south, the mountain Zec and Vranica in the Southeast, Vlašić in the west, and Tajan and Zvijezda in the north. The entry to the castle is on the southwest side, with two lookout towers.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.