Now if one follows the Via di San Francesco in from the gate of that name (see plate III again) and then continues down a narrow street east of the monastery as far as the open space in front of the church of Santa Maria del Carmine, he will see that on his left above him the slope of the mountain was not only precipitous by nature but that also it has been rendered entirely unassailable by scarping.[32] From the lower end of this steep escarpment there is a cyclopean wall, of the same date as the upper side walls of the town, and the wall of the arx, which runs entirely across the city to within a few yards of the wall on the east, and to a point just below a portella, where the upper cyclopean wall makes a slight change in direction.  The presence of the gate and the change of direction in the wall mean a corner in the wall.

[Illustration:  Plate III.  The western cyclopean wall of Praeneste, and the depression which divides Monte Glicestro.]

It is strange indeed that this wall has not been recognized for what it really is.  A bit of it shows above the steps where the Via dello Spregato leaves the Via del Borgo.  Fernique shows this much in his map, but by a curious oversight names it opus incertum.[33] More than two irregular courses are to be seen here, and fifteen feet in from the street, forming the back wall of cellars and pig pens, the cyclopean wall, in places to a height of fifteen feet or more, can be followed to within a few yards of the open space in front of Santa Maria del Carmine.  And on the other side toward the east the same wall begins again, after being broken by the Via dello Spregato, and forms the foundations and side walls of the houses on the south side of that street, and at the extreme east end is easily found as the back wall of a blacksmith’s shop at the top of the Via della Fontana, and can be identified as cyclopean by a little cleaning of the wall.

The circuit of the earliest cyclopean wall and natural ramparts of the contemporaneous citadel and town of Praeneste was as follows:  An arc of cyclopean wall below the cap of the hill which swung round from the precipitous cliff on the west to that on the east, the whole of the side of the arx toward the mountains being so steep that no wall was necessary; then a second loop of cyclopean wall from the arx down the steep western edge of the southern slope of the mountain as far as the present Porta San Francesco.  From this point natural cliffs reinforced at the upper end by a short connecting wall bring us to the beginning of the wall which runs across the town back of the Via del Borgo from Santa Maria del Carmine to within a short distance of the east wall of the city, separated from it in fact only by the Via della Fontana, which runs up just inside the wall.  There it joins the cyclopean wall which comes down from the citadel on the east side of the town.