The history of the Mesnil-Saint-Denis begins mainly into 768 when Pépin le Bref made gift with the abbey of Saint-Denis of most of the forest of Yveline, even if it is true that the Romans had already marked of their presence the place. At the Moyen Age, the representatives of the monks of the abbey came to perceive the incomes there.
It's for this reason and by safety measure that a known house strengthened under the name of "Ferté-Beaurain" was built. The village took then the name of Mesnil (group of houses) Saint-Denis (name of the parish fondatrice). It received the visite of the abbe Suger, Minister of King Louis VII, in 1144.
It's in 1543, under François 1st that Philippe Habert, clerk of the clerk's office criminal at the Parliament, acquired in the parish, of a house and grounds. It is his son Louis Habert de Montmor, treasurer of the Wars, adviser of State which, since 1589, undertook the construction of current the castel. Il will be livable since 1592. Habert de Montmor and their castle "regulated" the life of the Mesnil-Saint-Denis during nearly two centuries of 1543 to 1720. Louis XIV to thank this family sets up in 1650 Mesnil in County. The village then took the name of "Mênil-Habert". Their arms "of azure to the gold rafter accompanied by three irons of money mills" became in 1972 the blazon of the Mesnil-Saint-Denis.
Personalities of prestige attended the castle: Mrs. de Sévigné, the scientist Gassendi, Cyrano of Bergerac and Henry Le Bret, but also François-Hannibal Maréchal d'Estrées, brother of beautiful Gabrielle favorite of the king Henri IV, who marry in the church in 1634.
Significant events will punctuate the life of this commune: destruction of the bell-tower of the church by the lightning (1709), sale of the furniture of the castle (1718), baptism of bells by Jean-Louis du Rieu du Fargis in the presence Minister Maurepas (1729). The new lords of the manor, the family de Selle (1737-1805) will stick especially to the interior repair of the church and the paving of the streets. They will know the disorders of the Revolution (books of the complaints, Garde-Nationale, civic oath...). During this period, a former corsair living the castle of Ambésis, Jean-Baptiste Ernest Buchère de l'Epinois, ordering Garde-Nationale of Mesnil, will be guillotined (1794) to have plotted to deliver the Queen Marie-Antoinette of the Temple and to try to replace on the throne Louis XVII. It is also in this Ambésis small castle of the family that lived Rousseau dynasty masters of arms, who taught fencing to our kings of France, Louis XIV to Louis XVI, and François Jacques Antoine Mathieu de Reichshofen, lawyer and diplomat from Alsace.
Under the First Empire, two famous characters left their names attached to our church: Antoine-Marie Chamans count de Lavallette, lord of the manor of La Verrière, Postal Minister, there buried her father (1808) and Martin-Guillaume Biennais, goldsmith appointed of the Emperor, was the godfather of one of the new bells (1829). The Chateau du Mesnil is then the property since 1805,  Etienne Dominique Pierre Cureau de Roullée.
In 1846, Ernest Picard, Minister for Finance of Napoleon III, will settle with the castle of Grands-Ambésis where it accepted there great names of the policy of this time, Jules Favre, Jules Ferry, Emile Ollivier.
On this same date, was made the decision to transfer the old cemetery which was located around the church.
During the war of 1870, the castle pertaining to the Husson family was occupied by the Prussians. This family made build the chapel of the castle (1884) like for their daughter, the monastery of Mousseau, inaugurated in 1895. It was the occasion for the village of great festivities.
The XXe century modifies the everyday life of French and his urban landscape: 1906 - installation of gas burners, 1925 - Electricity due to the generosity of Leon Bobin, notable of Mesnil, 1926 - Creation of the subdivision Henriville, 1947 - Establishment of the factory of ball point pens Reynolds in the castle which it buys the same year, 1965 - Construction of the Residences of the castle by the Company Levitt and Sons (it will be the first operation of construction in great series of individual residences carried out in France since the Second World War) - 1971 - Construction of the post office, of a college and a sporting complex - 1973 - Realization of Champmesnil.
During the two world wars, one will note that the monastery been used as auxiliary hospital and that the hamlet of Rodon was bombarded (1944).
Character determining for the future of the village: Me Raymond Berrurier, notary and former mayor of the commune of 1938 to 1967, made in the name of this one the acquisition of the castle (1952) to transform it into town hall-school (1955). We owe him what is Mesnil of today: "a city in the countryside".
Since 1984, this city is integrated in the Regional Natural reserve of the High Valley of Chevreuse, enabling him to defend its historical inheritance, the charm of its rural life and its island of greenery.
Since 1985, the Mesnil-Saint-Denis is twinned with the German city of Hankensbüttel in Low-Saxony.
With the last census, the Mesnil-Saint-Denis counts 6.634 inhabitants, with the hamlets of Rodon and Le Mousseau and Small and Large Ambésis.
Copyright © Olivier FAUVEAU - 2001