The Castle of Monção was built by King Denis of Portugal in 1306 and it was enlarged in 1656. From the original castle, the only remains are two doors, some pieces of the medieval wall, and the Torre de Lapela Towers, which shows off the coast of arms of King Ferdinand I.
From the walls, the only remain is the main door, defended by the Keep, with a Gothic style; and the treachery door, with a smaller size. From the 17th century fortress there are many parts still standing, such as the Porta de Salvaterra Door and some bastions.
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.