It is best known as being the private residence of the second spouse of Louis XIV, Madame de Maintenon (1635-1719). (The marriage was never officially recognized). The construction of the château began in the 12th and ended roughly in the 18th century. In the early 16th century it was purchased by Louis XII's treasurer Jean Cottereau, who transformed the château-fort into a country house. In the 17th century it was rebuilt for Madame de Maintenon, who purchased the estate in 1675. The château's main features are the keep, constructed in the 13th century, and the principal corps de logis, flanked by two round towers. It is surrounded by a large moat with water. Le Notre was involved with smaller gardens and the main parterre at Maintenon (1675-1678). At the far end, cutting through the gardens, is the aqueduct built from 1685 to supply the fountains of the park of the Palace of Versailles. The project meant that water was diverted from the Eure river some 80 km away. The arches of the structure reach a height of 60 feet. Vauban was in charge of the works.