A first thesis, that of RP Fouquet, fixed the Foundation of Montoussan around 1150 by Hugh, Lord of Amboise, Montoussan reported to the Château of Amboise, as evidenced of confessions made on December 22, 1547 and 29 September 1766.
In 1792, the Priory was sold as national goods to Guiot, notaire, In 1826, the Duke of Orléans purchased the Priory, demolished the buildings North of the chapel and in 1842 built instead wooden outbuildings. Confiscated in 1852 and returned in 1871, the Priory was attributed to the Duchess of Saxe-Coburg and Gotha, daughter of King Louis-Philippe.
The main entrance door was opened at the West end, in the south wall, at one metre fromthe southwest corner; the frame no longer exists and the dimensions are given by the upper part of the segment that has a width of 2 metres, a height of three metres. The building is rectangular in shape and ended to the is by a three sided apse, encountered by many buttresses, which one survives in the North wall.