The construction of Paide order castle was started in 1265 under the leadership of Konrad von Mandern. The original tower of Tall Hermann was octagonal with the height of over 30 meters and the thickness of the walls of about 3 meters.
At the beginning of the Livonian War the Russians repeatedly besieged Paide, but only in 1573 they finally managed to invade Paide. After that it changed hands several times until the Swedes got it in 1608. In 1638 they removed Paide from the list of castles.
The rampart tower and castle ruins were first conserved at the end of 19th century. In 1913 a park was planted on the hill. In 1941 Soviet soldiers destroyed the rampart tower, the symbol of both Paide and Järva County. To celebrate the 650th anniversary of the St. George's Night uprising the tower was restored in 1993. Today it houses a 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.