The origins of the Castillo de la Yedra could be Muslims, possibly from the Almohad era. During the 11th and 12th centuries, the first fortress was built, but the current appearance was built by Christians during the 13th and 14th centuries and during the papacy of don Pedro Tenorio. The alcázar was built by the archbishops of Toledo at the end of the 14th century. There is a keep and a small parade ground that surround the alcazar.
Its construction was designed exclusively for military use as a palace of a feudal lord or small court of medieval monarch. That is why its architecture is sober, although compensated by the beauty of the topography of its location and the surrounding landscape.
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.