Perchtoldsdorf Castle probably was laid out before 1000 AD, part of a chain of fortifications along the eastern rim of the Vienna Woods. One Lord Heinricus de Pertoldesdorf was mentioned in an 1138 deed, during the Babenberg rule. Their Perchtoldsdorf vassals continued to rule from the castle even when the Babenberg dynasty became extinct in 1246.
The conflict between the Habsburg emperor Frederick III and his younger brother Archduke Albert VI of Austria started an unstable period in the region. In 1446, many homes in the town were burned during the invasion of the Hungarian regent John Hunyadi. During this time, the castle was occupied by various rival forces, including mercenaries of King Matthias Corvinus from 1477 until about 1490, when Frederick's son King Maximilian I re-established Habsburg control over the area. This turbulent period interrupted the construction of the tower house (Wehrturm), the town's landmark with a height of 60 metres. The tower and other fortifications permitted a successful defense of the city against the Ottoman troops during the 1529 Siege of Vienna, while the surrounding area was devastated.
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.