Schloss Grafenegg, originally a small settlement called Espersdorf in 1294, evolved into its present form over centuries. It received its name in the 15th century and went through various ownership changes, passing to Holy Roman Emperor Frederick III and later the Thurzó family. In the 17th century, it was fortified by Johann Baptist Verda von Verdenberg during the Thirty Years' War.
The castle's transformation continued in the 19th century under the Breuner-Enckevoirt family, who reconstructed it in the romantic historicism style. The financial crisis of 1873 halted some planned expansions, preserving the castle's character. Marie Breunner-Enckevoirth inherited it and passed it on to the ducal house of Ratibor and Corvey when she married Viktor II, Duke of Ratibor and Prince of Corvey.
While not their main residence, the castle remained in their possession until it was heavily damaged during the Russian occupation in 1945-1955. Restoration efforts by Franz-Albrecht, who adopted the Metternich-Sandór name, began in 1967, with support from Austrian authorities. Today, Schloss Grafenegg is open to the public.
The 19th century conversion by the architects Leopold and Hugo Ernst left the nucleus of the existing building almost fully intact. However, they gave the castle exterior a completely different impression by adding stepped gables, arcades and facade decoration in a neo-gothic Tudor style. Ludwig Wächtler was responsible for the interior decoration, which was largely in Renaissance Revival architecture. The closed complex consists of four wings arranged around an inner courtyard.
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.