The withdrawal of the garrisons did not imply giving up possession, strictly speaking, of the right bank in this province. It was looked upon by the Romans thenceforth somewhat as the commandant of a fortress looks upon the ground that lies under his cannon. The Cannenefates and at least a part of the Frisians[68] were afterwards subject, as before, to the empire. We have already remarked that subsequently in the Münster country the herds of the legions still pastured, and the Germans were not allowed to settle there. But the government thenceforth relied--for the defence of such border-territory on the right bank as still existed in this province--in the north on the Cannenefates and the Frisians, and farther up the stream substantially on the space left desolate; and, if it did not directly forbid, at any rate did not give scope to Roman settlement there. The altar stone of a private person found at Altenberg (circuit of Mülheim), on the river Dhün, is almost the only evidence of Roman inhabitants in these regions. This is the more remarkable, as the prosperity of Cologne would, if special hindrances had not here stood in the way, have of itself carried Roman civilisation far and wide on the other bank. Often enough Roman troops may have traversed these extensive regions, perhaps even have kept the roads--which were here laid out in large number during the Augustan period--in some measure passable, and possibly laid out new ones; sparse settlers, partly remains of the old Germanic population, partly colonists from the empire, may have settled here, similar to those that we shall soon find in the earlier imperial period on the right bank of the upper Rhine; but the highways, like the possessions, lacked the stamp of durability. There was no wish to undertake here a labour of similar extent and difficulty to that which we shall become acquainted with further on in the upper province, or to provide here, as was done there, military defence and fortification for the frontier of the empire. Therefore the lower Rhine was crossed doubtless by Roman rule, but not, like the upper Rhine, also by Roman culture. [Sidenote: The situation in Gaul and Germany after the fall of Nero.]