The castle of Montealegre, built in the 12th century, was mentioned for the first time in 1173, when Rodrígo Gutiérrez was appointed lord of Montealegre; together with the castles of Ampudia, Belmonte, Torremormojón, Medina de Rioseco, Mucientes and Trigueros, it formed the defence line of the southern border of the Kingdom of León. The castle was revamped in 1297 by Alfonso Tello Pérez de Meneses, appointed lord of Montealegre by King Alfonso VIII.
In the 13th century, the domain was transferred to the Order of Saint James, which granted a charter to the village in 1219. Further owners of Montealegre were the Albuquerque (14th century), who defended the castle against King of Castile Peter the Cruel in 1354, and the Manuel (15th-17th centuries). The Manuel family maintained in the town one of the most significant Jewish communities in the province. In 1626, Montealegre became a Marquisate, granted by King Philip IV to Martín de Rojas y Guzmán.
The present castle, with its austere and strong appearance, has a slightly trapezial groundplan, with four strong towers at its corners. Three of them are rectangular and the fourth is pentagonal and served as the keep. In the middle of its curtain walls it is fitted with slender circular towers. The height of its walls range from 18 to 24 meters with a thickness of 4 meters. With its functional and horizontal impression it represents an adoption of a Mediterranean-Arab castle, a style known in Europe from the 13th century.
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.