Frankenberg Castle was constructed during the 13th century and historically it was the seat of a Vogt, local administrator. Until the end of the 19th century, the castle consisted of a broad forecastle, a farmyard, and a main castle (which was completely surrounded by water).
With the introduction of the French Constitution of 1793, Frankenberg Castle lost its status as a fief of Jülich. Between 1834 and 1838, the property underwent comprehensive renovation and modernization.
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.