In 1393, Louis d’Orleans, second son of Charles V, established a fortified residence built over the site of an original fortress constructed by the descendants of Nivelon of Pierrefonds in the 12^th century.

This fortress, close to Compiègne, remained as a royal grant to the Orléans family, first Charles, son of Louis, and then the future Louis 12^th. In  1589  Antoine de Saint-Chamand took the castle over in the name of the Holy League.

The Railroad Company and the Ministry for Public Works were in favour of the finally choosed site of Beaudon. The train passengers would thus see the castle on their arrival, and the area of Beaudon moreover had serveral hostels.

Saint-Sulpice church was founded between 1060 and 1070 by Nivelon, the first lord of Pierrefonds. Sulpice was the archbishop of Bourges and advisor to king Clotaire II, he became bishop in 624.

The crypt is the only element that remains from Romanesque period. Nivelon, who died in 1072, is buried there. Many pilgrims used to come to Saint-Supilce church : indeed, there was in the crypt a spring which water was known to heal fevers.