In a military as well as a political sense the shifting of the frontier, or rather the strengthening of the frontier-fence, was effective and useful. While formerly the Roman chain of forts in upper Germany and Raetia probably went up the Rhine by way of Strassburg to Basel and along by Vindonissa to the lake of Constance, then from thence to the upper Danube, now the upper German headquarters were in Mentz and the Raetian in Ratisbon, and generally the two chief armies of the empire were brought considerably nearer to each other. The legionary camp of Vindonissa (Windisch near Zürich) became thereby superfluous. The army of the upper Rhine could, like the neighbouring one, be reduced after some time to the half of its former strength. The original number of four legions, which was only accidentally diminished to three during the Batavian war, subsisted, at all events, probably still under Trajan;[90] but under Marcus the province was only occupied by two legions, the 8th and the 22d, of which the former was stationed at Strassburg, the second at the headquarters Mentz, while most of the troops, broken up into smaller posts, were stationed along the frontier-wall. Within the new line urban life flourished almost as on the left bank of the Rhine; Sumelocenna (Rottenburg on the Neckar), Aquae (_civitas Aurelia Aquensis_, Baden), Lopodunum (Ladenburg), had, if we except Cologne and Treves, to fear no comparison as respects Roman urban development with any town of Belgica. The rise of these settlements was chiefly the work of Trajan, who began his government with this act of peace;[91] "the Rhine Roman on both its banks" is what a Roman poet entreats speedily to send to Rome its yet unseen ruler. The great and fertile region, which was placed in this way under the protection of the legions, needed that protection and was worthy of it. Doubtless the battle of Varus marks the beginning of the ebb of Roman power, but only in so far as its advance was thereby ended, and the Romans thenceforth contented themselves in general with shielding more vigorously and continuously what was retained. [Sidenote: Germany under Marcus.]