It was probably built on the site of a Roman camp, as evidenced by the still visible remains of the paving of a Roman road. According to comments on the Gallic Wars (58-52 avJC), Julius Caesar after the siege of Avaricum ( Bourges ) held its twelfth legion with this strategic region who commanded the Roman road branching off Tincontium ( Sancoins ) to a Avaricum both Auvergne other. The vi th century , about 620? St. Columba , an Irish monk came to evangelize the Gaul after the disturbances caused by the barbarian invasions, gave the task to one of his disciples nicknamed Theodulf Bobolein and Saint Chalan create a monastery in Jouy on l'Aubois on the site of the Roman fort. (In 620 was also built by Bobolein Abbey Bellavaux in Charenton-du-Cher ). The trenches of the former Roman camp were used for the construction of the monastery which stood on a smaller enclosure than the camp itself and included cells, a well, a church, a cemetery and at the north end a square tower was certainly leveled to build the dungeon. This monastery was destroyed between the viii th and ix th century when new invasions by the Hungarians.