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:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.