In the 1st century BC, the site was originally a major settlement near the ford that enabled the Cahors (Divona)-Toulouse (Tolosa) road to cross the Aveyron river. In 961, Raymond I, Count of Rouergue, bequeathed the lands, castles and churches of Cos to the Abbey of Moissac.
In 1628, the Wars of Religion left the Catholic population of Ardus battered and the buildings of Ardus and Cos (mill, castles, churches) in ruins. François Duval took the title of Baron de Lamothe in 1734, built the present Château on the banks of the Aveyron and became owner of the Moulin. In 1737, he founded an earthenware factory, the first Montalban establishment to obtain the title of Manufacture Royale in 1739.