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:
The Château Comtal (Count’s Castle) is a medieval castle within the Cité of Carcassonne, the largest city in Europe with its city walls still intact. The Château Comtal has a strong claim to be called a 'Cathar Castle'. When the Catholic Crusader army arrived in 1209 they first attacked Raymond-Roger Trencavel's castrum at Bèziers and then moved on to his main stronghold at Carcassonne.
The castle with rectangular shape is separated from the city by a deep ditch and defended by two barbicans. There are six towers curtain walls.
The castle was restored in 1853 by the architect Eugène Viollet-le-Duc. It was added to the UNESCO list of World Heritage Sites in 1997.