Cornštejn Castle stands on a strategic location, surrounded by magnificent landscape of the Dyje (Thaya) River Valley. It was built on royal demesne land which was subordinated to Bítov Castle and which was pawned and later (1308) granted as a fief to the noble family of Lichtenburg. In the 1320s Raimund of Lichtenburg, King Wenceslaus II’s favourite, decided to strengthen the security of Bítov Castle and the road connecting Bítov with Vranov Castle by building Cornštejn.
Originally a small Gothic noble residence with a Courtyard, a high enclosing wall and a palace (guarded by a high shield-wall) gradually developed into a large medieval fortress. In the latter half of 14th century Henry of Lichtenburg built a pre-wall around the whole castle, which is how the Upper Bailey came to being. In the first third of 15th century Albrecht and John of Lichtenburg and Zornstein erected another palace on the other side of the Courtyard and established the Lower Ward with barracks and some other buildings, surrounded by a new ring of curtain walls with two new gates and two bastions.
In 1422 the castle was besieged by the Hussite troops, which afterwards made the lords of the castle fortify the dangerous strategic hill south of Cornštejn with a detached outwork. Cornštejn was again sieged eleven months by King George of Bohemia in 1463. However, Cornštejn turned out to be impossible to be stormed in a few days. King George punished Hynek and confiscated the castle. Cornštejn was subsequently granted to Wolfgang Kraiger of Kraigk who reconstructed the castle and modernised both the palaces. His sons Lipolt and Henry then built an up-to-date advanced fort on the rocky platform south of the castle, reflecting latest trends in artillery warfare. After 1526 the castle got back into the hands of the Lichtenburgs of Bítov. In 1542 the Moravian Estates ordered that Cornštejn be repaired and improved so as to withstand a possible Turkish assault. Fortunately, the Ottoman army never made it to southern Moravia, and Cornštejn was spared.
However, the time of medieval castles was over by the late 16th century and there was no need to maintain Gothic fortresses any longer. After the Lichtenburgs died out in 1576, the new owners – Streuns of Schwarzenau abandoned the castle and may well have got all roofs removed (so as not to pay tax). Thus Cornštejn began to fall into ruin and none of the noble families that owned the castle after the Streuns (1617 Jankovský of Vlašim, 1788 Counts von Daun, 1912 the Haases von Hasenfels) would change anything about it. In 1945, Cornštejn was confiscated from the Haases and nationalised. In the early 1970s two thirds of the castle were reconstructed by the Monument Preservation Institute, Brno. The castle ruins have been stabilised and since 1998 open to public.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.