In the 10th century the first church was built in the village but it was quickly ruined.
In 1006 the rebuilding of the church and steeple was entrusted to the Benedictine monks of the Abbey of Saint-Maur by Renaud de Vendôme, bishop of Paris and it was consecrated to Pope Clement I. They added a cloister, a priory, and a tithe barn.

A document dated 1265 attests to the presence of a Hotel-Dieu at Arpajon for the accommodation of travelers and the poor.
There were also several mills on the Orge and the Rémarde.
The town was fortified and had five entrances.

In 1317 Pierre de Chastres was buried in the parish church.
In 1360, during the Hundred Years War, the city was besieged by King Edward III of England and the church where there were eight hundred refugees was burned leaving no survivors.

In 1470 the lordship of Chastres belonged to the lord of Marcoussis.
In July 1470 King Louis XI authorised two fair days at Chastres for his counselor and chamberlain Jean du Graville by letters patent.
Louis Malet de Graville built a Market hall at the crossroads of the Paris to Étampes and Dourdan to Corbeil roads.

In 1510 the monks, through the generosity of the Graville and Montagu families undertook major renovations of the church and in 1542 a sub-delegation of Chastres was attached to the Generality of Paris.
In 1545 the lordship of Chastres became independent.

In 1643 the bell named Antoinette was cast.
On 28 April 1652 Turenne stationed his troops at Châtres to protect the court at Saint-Germain before he marched on Étampes on 3 May.
In 1717 the Hotel-Dieu was completely rebuilt.
In 1720 Louis de Severac, Marquis of Arpajon from the great medieval family of Arpajon, bought and obtained from Philippe d'Orléans the privilege of giving his name to the commune.
However, the adoption of the new name took a long time and peasants who refused to abandon the name of Châtres were beaten up.
He also promised to reduce local taxes for two years.
The Canting arms of the city come from this family.
In 1733 he knocked down the old city gate in the north which was too narrow for many carts and instead erected two Pilasters which are the current Porte de Paris.
He died on 21 August 1736 and was buried in the choir of the parish church.
In the 10th century the first church was built in the village but it was quickly ruined. In 1006 the rebuilding of the church and steeple was entrusted to the Benedictine monks of the Abbey of Saint-Maur by Renaud de Vendôme, bishop of Paris and it was consecrated to Pope Clement I. They added a cloister, a priory, and a tithe barn.
A document dated 1265 attests to the presence of a Hotel-Dieu at Arpajon for the accommodation of travelers and the poor. There were also several mills on the Orge and the Rémarde. The town was fortified and had five entrances.
In 1317 Pierre de Chastres was buried in the parish church. In 1360, during the Hundred Years War, the city was besieged by King Edward III of England and the church where there were eight hundred refugees was burned leaving no survivors.
In 1470 the lordship of Chastres belonged to the lord of Marcoussis. In July 1470 King Louis XI authorised two fair days at Chastres for his counselor and chamberlain Jean du Graville by letters patent. Louis Malet de Graville built a Market hall at the crossroads of the Paris to Étampes and Dourdan to Corbeil roads.
In 1510 the monks, through the generosity of the Graville and Montagu families undertook major renovations of the church and in 1542 a sub-delegation of Chastres was attached to the Generality of Paris. In 1545 the lordship of Chastres became independent.
In 1643 the bell named Antoinette was cast. On 28 April 1652 Turenne stationed his troops at Châtres to protect the court at Saint-Germain before he marched on Étampes on 3 May.
In 1717 the Hotel-Dieu was completely rebuilt. In 1720 Louis de Severac, Marquis of Arpajon from the great medieval family of Arpajon, bought and obtained from Philippe d'Orléans the privilege of giving his name to the commune. However, the adoption of the new name took a long time and peasants who refused to abandon the name of Châtres were beaten up. He also promised to reduce local taxes for two years. The Canting arms of the city come from this family. In 1733 he knocked down the old city gate in the north which was too narrow for many carts and instead erected two Pilasters which are the current Porte de Paris. He died on 21 August 1736 and was buried in the choir of the parish church.
Arpajon