Rupelmonde Castle was built by the Counts of Flanders in the 12th century directly opposite the mouth of the river Rupel into the Scheldt river to defend these rivers. It was a large fortress with 17 towers circled by a moat. From this castle toll was levied from passing ships. Later on the castle was also used as a state prison. This caused the castle to play a important role in the history of the region.
In 1678, when Spanish and Dutch troops were fighting against French troops, the castle was destroyed. The castle was never rebuilt and turned into a quarry for cheap building materials for the locals. In 1817 the castle ruins were demolished with exception of a base of a tower with some connecting wall fragments. On these remains then a tower out of red Tournai limestone was built by Baron De Feltz. This tower was used as a hunting pavilion.
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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.