In any case, the Roman walls, built we may think in the fourth century, enclosed an irregular quadrilateral, and possessed four gates out of which issued those four roads to Old Sarum, to Silchester, to Clausentum and to Porchester.

There are strangely grouped ruins, the remains of arcades, half-unroofed cupolas, columns without capitals, the shafts of which have retained all the brightness of their enamelling; then a long row of elliptical porticoes closing in one side of the vast quadrilateral.