Château de Breteuil is built on a promontory overlooking the Chevreuse Valley. For most of its existence, the castle has been known as Bévilliers -from latin bis villae (two villas)- which implies that this property would date back to the gallo-roman period.
The first estate appears in History as early as 1066 with Guillaume Osbern, the first Breteuil, who was Seneschal to the Duke of Normandy. Guillaume Osbern took part in the conquest of England by William the Conqueror, who saw him as his most faithful companion. In the summer of 1067 the King returned to Normandy, leaving the Lord of Breteuil and his brother in charge of England in his absence.
At the time, a fortified castle was built in Bévilliers; its dovecote and moats still remain today. In 1596, Thibaut Desportes bought the estate still called Bévilliers. Bordered by medieval square moats, a new castle was laid out around an enclosed courtyard, A pleasure garden was carefully thought out, situated at the foot of the north facade, so that the sun never glares into the eyes of the person contemplating it.
The curtain walls were removed and moat dried in 1820-1830. The major restoration took place in the end of the 19th century: two wings were added and the gardens were extended.
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.