Established from 1332 to 1339 as a foundation endowed by the wealthy patrician Konrad Groß for the elderly and needy. Considered the largest private endowment by any individual before 1500.
The Hospital of the Holy Spirit was established in 1332–39 by Konrad Gross, a wealthy patrician, for the care for the elderly and needy. It was the largest private endowment in the Holy Roman Empire up to 1500. After 1500 the building complex was extended over the Pegnitz according to plans by Hans Beheim the Elder. Two structures along the southern arm of the river and the north wall of the former hospital church with its polygonal ridge-turret survive.
From 1424 to 1796, the imperial regalia were kept in the hospital church (not reconstructed after the war). In the arcaded Kreuzigungshof, there are the central figures of Adam Kraft’s Crucifixion group (ca 1506/08) and the tomb monuments of Konrad Gross (d. 1356) and Herdegen Valzner (d. 1423).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.