It was built on the place where in Roman times the "big wall" had been erected as a walkable barrier. In the sixteenth century the wall was transformed into a mighty castle with corner bastions. Inside were frescoes of the 16th - 17th centuries. It previously belonged to the Filippeschi family and after to the noble family of the Conti of Marsciano, and it has given rise to Carnaiola village, from the linear form.