Located at an altitude of 443 metres at the end of the ridge, Château de l'Ortenbourg was built between 1260 and 1265 by Rudolf Habsburg to the site of older castle. It is one of the most beautiful ruins in the Rhine Valley.
In 1291, on the death of Rudolf, Otto IV opposed the election of Albert of Habsburg and supported Adolphe de Nassau. In 1293, Otton joined the siege and had the Ramstein built to take Ortenbourg; and after three weeks of sieges, the Austrians surrendered and the Val de Villé was invaded by Otto.
From the 16th century the castle started to dilapidate as a result of a lack of maintenance, although it is inhabited until the beginning of the 17th century. In 1633 the Swedes set fire to the castle.
Today Ortenbourg is a masterpiece of military architecture with its high shirt surrounding a 32-meter dungeon, is visible from a distance and fits remarkably in the landscape. This dungeon offered 6 levels of defensive fire and its pentagonal design allowed for better deflection of the attackers' projectiles.
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.