 With the fall of the Western Empire in the 5th century, the amphitheatre became a shelter for the population and was transformed into a fortress with four towers (the southern tower is not restored).The structure encircled more than 200 houses, becoming a real town, with its public square built in the centre of the arena and two chapels, one in the centre of the building, and another one at the base of the west tower.This new residential role continued until the late 18th century, and in 1825 through the initiative of the writer Prosper Mérimée, the change to national historical monument began.