Pajštún Castle was built in 13th century as part of a regional castle system aimed at defending the north-western border of the Kingdom of Hungary. One of the first known records mentioning the castle comes from 1314 in connection to its owner, Otto from Telesprun; many sources often, mistakenly, date the first mention of the castle to 1273. In 1390, Sigismund, the Holy Roman Emperor and King of Hungary at the time, gifted the castle to the Grafs of the nearby Svätý Jur and Pezinok.
Since 1592, the castle belonged to the influential Pálffy family. However, its condition has been progressively worsening, and with the looming Turkish danger at the time, the castle has undergone major repairs around 1645, led by an Italian engineer Filiberto Luchese, which fundamentally transformed the original 13th century core of the castle. Nevertheless, the owners of the castle soon started preferring other locations of greater convenience, and Pajštún's significance - and condition - began to decline. This was aggravated by a large fire in the mid-18th century which destroyed a large part of the castle. With its importance diminished, the repairs were merely provisional. The final blow, however, came in 1810, when Napoleon's army destroyed the castle with an explosion. The destruction was deemed unnecessary, as the castle was already abandoned and posed no military threat. The last owner of the castle, Ľudovít Károlyi abandoned his properties in 1945, the ruins of the Pajštún Castle along with other nearby mansions and possessions among them.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.