Ehrenfels Castle was probably built in the first half of the 13th century. The first mention of the Lord of Ehrenfels is in 1257. In 1320 it was owned by Burkhard and Rudolf von Schauenstein, who also used the name Ehrenfels or Herrenfels. They probably expanded the simple bergfried with residential space and a ring wall around that time. The castle was first mentioned in 1423 with Hermann von Ehrenfels as the owner. Toward the end of the 15th century or in the early 16th century it was given to Cazis Monastery, but the Schauenstein-Ehrenfels family continued to occupy it. During the 16th century the castle was renovated and rebuilt into a more comfortable palas.
However, by 1600 Ehrenfels was abandoned and began falling into ruin. Parts of the castle were demolished for building material, and when the Ehrenfels-Schauenstein male line died out in 1742, only a ruin remained. In 1933 it was acquired by the Schweizerische Burgenverein (Swiss Castle Association) and converted into a youth hostel. Since the conversion was done without archeological investigation or records, much of the history of the castle was lost. In 1954 Swiss Youth Hostels bought the castle from the Association. It remains in operation today with 38 beds.References:
Ängsö Castle was first named as "Engsev" in a royal charter by king Canute I of Sweden (r. 1167-1196), in which he stated that he had inherited the property after his father Eric IX of Sweden. Until 1272, it was owned by the Riseberga Abbey, and then taken over by Gregers Birgersson.
From 1475 until 1710, it was owned by the Sparre family. The current castle was built as a fortress by riksråd Bengt Fadersson Sparre in the 1480s. In 1522, Ängsö Castle was taken after a siege by king Gustav Vasa, since its owner, Fadersson's son Knut Bengtsson, sided with Christian II of Denmark. However, in 1538 it was given by the king to Bengtsson's daughter Hillevi Knutsdotter, who was married to Arvid Trolle.
In 1710, the castle was taken over by Carl Piper and Christina Piper. Ängsö Castle was owned by the Piper family from 1710 until 1971, and is now owned by the Westmanna foundation. The castle building itself was made into a museum in 1959 and was made a listed building in 1965. It is currently opened to visitors during the summers.
The castle is a cubical building in four stores made by stone and bricks. The lower parts is preserved from the middle ages. It was redecorated and expanded in the 1630s. The 4th storey as well as the roof is from the expansion of Carl Hårleman from 1740-41. It gained its current appearance in the 1740s.