Once past Via Montebello, one comes to one of the small postern gates (posterulae) dating to the first phase of the construction of the Walls: its right doorjamb and travertine architrave made lighter by two arches in opus latericium or ancient Roman brickwork are clearly visible. It is likely that this gate was built to enable the passage of a secondary road that could not be eliminated by the new Walls, perhaps because it served several important properties or the nearby Castro Pretorio barracks. A short time after its construction, this posterula or postern was closed with a wall in opus latericium very similar in technique to that of the first phase of the Walls.