In 1211 Riga's archbishop Albert inaugurated Theodorich as the bishop of Estonia. The centre of the bishopric was to be in Lihula. The Construction of the Bishop's Castle began after the conquest of Estonia, namely in 1238 and it was finished in 1242. The bishop shared the castle with the Order. Their relationship became however quite tense and the bishop soon began to look for a more peaceful location. In 1251 the bishop moved to Old-Pärnu and in 1279 to Haapsalu.
The main castle was located on an oval-shaped hilltop, surrounded by a wall, which was at the same time an outer side of the buildings. The north and west sides of the hill were steep, the south and east sides shelving. For that reason the castle was protected from the south and east with two outworks separated by dry moats and stone walls.
During the Livonian War (1558-83) the castle repeatedly changed hands and it was greatly damaged. It was last besieged in 1581. After the war it was decided that the castle would not be restored and in 1643 the Queen of Sweden gave the permission to demolish it.
In 1990-1996 archaeological excavations were carried out on the east side of the main castle, where the walls of the pre-defence system of the main gate were uncovered. Research has shown that the Bishop's Castle of Lihula is one of the most unique defence buildings from the 13th century in the Baltic.
Reference: Lihula Museum
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.