Alberweiler Castle is a small castle-like structure where the ground and the first floor of the castle are made of stone and the upper storeys consist of three projecting half-timbered floors.
A castle is first mentioned in sources dating from the 11th century. It was occupied by knights in the service of the Counts of Berg-Wartstein. This early structure was destroyed in 1487 but soon after, towards the end of the 15th century, a new castle was erected at the behest of Bartholome of Warthausen. Some remains of the circular rampart are still visible. Following the extinction of the house of Warthausen zu Alberweiler in 1585, the castle was enfeoffed to the Counts of Stadion by Emperor Rudolf II. The castle was renovated in early-Baroque style in the 17th century. The gate was also constructed during these restoration works. At around 1700, the castle functioned as residence for the local reeve, the Counts of Stadion residing at Warthausen Castle, and subsequently went into private ownership during the course of the 18th century. In 1826, the Counts of Stadion sold all rights to the village and the castle to the Kingdom of Württemberg. Following alterations in 1880 the structure slowly began to fall into disrepair. The castle was extensively restored in the late 20th century and is privately owned today.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.