Ferentino still possesses remains of ancient fortifications. The lower portion of the outer walls, which probably did not stand free, is built of roughly hewn blocks of a limestone which naturally splits into horizontal layers; above this in places is walling of rectangular blocks of tuff. Two gates, the "Porta Maggiore", a double gate constructed entirely of rectangular blocks of tuff, and the "Porta Sanguinaria" (with an arch with tuff voussoirs), are preserved. Outside this gate, the testament of Aulus Quinctilius Priscus inscribed in the rock.