To be privately owned
Ennsegg Castle

In the city of Enns, Ennsegg Castle is a historic structure that was once part of the city's fortifications.
History+
The origins of Ennsegg Castle date back to the late 15th century, when Emperor Frederick III ordered the construction of a new princely castle on the Ennsberg in 1483, as the previous Ennsburg on Georgenberg was dilapidated. A hundred years later, this new building was also in poor condition, leading to considerations for another reconstruction in 1565. Despite the city of Enns' interest in acquiring the old castle, Emperor Maximilian II transferred ownership to his court vice-chancellor Georg Gienger. Between 1565 and 1570, Gienger had the current Ennsegg Castle built, which was initially smaller than the present complex. After Gienger's death in 1577, ownership changed hands several times until David Ungnad von Weissenwolff repurchased the castle in 1656 and had it expanded with the two large courtyard wings.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:Enns_03.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 48.2154, 14.4814