Innerjuvalt was built about 2 km south-east of the older Hochjuvalt Castle by the Freiherr von Juvalt. It was built in two parts on a narrow rocky outcropping above the entrance to the Domleschg Valley. The upper castle was first built around 1250 and was expanded around 1273. In 1342 two of the von Juvalt family, Albrecht and Bertram, appeared in a probate court to settle their inheritance, with Bertram giving up his rights to Innerjuvalt. In 1372 Elgof and Friedrich von Juvalt divided the inheritance again, with Eglof receiving the castle, its meadows, a mill and vineyards. In 1382 Egolf's wife Ursula was living in the castle. In 1423 Rudolf von Juvalt was ordered to continually live in the castle, but by 1440 they had moved to the more accessible lower castle. However, they added a third story to the tower in the late 15th century.
In 1462 Barbara von Juvalt sold the castle to her brother in law Pedrutt von Wannis. A few decades later it was abandoned and by 1570 was described as a ruin.
The upper castle was built around 1250 as a two story palas, probably to house workers as they completed the castle. A two story main tower and an attached residential wing were added to the north-east of the palas. A third story was added to the tower in the late 15th century. A wall was built on lower western side of the outcropping, with the remainder protected by steep cliffs. A bakery and a cistern were built along this wall. Beginning in 1979 the communities of Domleschg and the Burgenvereine Graubünden added a new roof and repaired and rebuilt the castle. The ruins were excavated in 1980, 1982 and 1990. Today the castle grounds are open for visitors and the tower can be rented by small groups.
The lower castle was built at the foot of the cliff. It consisted of a ring wall with a gatehouse on the southern side. A large palas or residential building was built along the wall. The northern side of the courtyard was terraced for farming. Today very little of the lower castle remains.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.