Riddagshausen Abbey was a Cistercian monastery just outside the city of Braunschweig in Germany. It was founded as Marienzelle by Ludolf the Wend, a ministerialis of Henry the Lion and steward of Brunswick, and settled in 1145 by monks from Amelungsborn Abbey. Henry endowed the new foundation in 1146 with the neighbouring village of Riddagshausen, from which it took its name. The abbey early acquired reichsunmittelbar status as an Imperial abbey.
It was mediatised in 1569 by Brunswick-Wolfenbüttel, when it became a Protestant establishment. From 1690 it was also the home of a prestigious Lutheran seminary for training of preachers, the first in Germany. The religious community and the seminary were dissolved in 1809.
The surviving buildings include the abbey church and the gatehouse, now home of the Cistercian Museum.
References:Duino Castle was built by the Wallsee family in 1389 on the cliffs overlooking the Gulf of Trieste. It replaced an older castle from the 11th century. Over time, the Wallsee family disappeared and the castle, after having been used as a prison, became the residence of the Luogar and Hofer.
At the end of the 19th century it became the property of Prince Alexander von Thurn und Taxis from the Czech branch of the House of Thurn and Taxis. It remains with the family to this day with his great-grandson Prince Carlo Alessandro della Torre e Tasso, Duke of Castel Duino the current owner. The castle has been opened to the public as a museum and park.