The Roman Frontier in Germania

Augustus began a forward policy aimed at securing north Italy by occupying the Alpine massive and by pushing back the tribes on the Rhine to a more defensible frontier. His step sons Drusus and Tiberius, using massive numerical superiority, cleared the central Alps and their northern foot hills.

Simultaneously, the legions and their auxiliaries in Gaul, were pushed forward to the Rhine. Nijmegen, Xanten, Köln, Neuss, Mainz, Augsburg, and Dangstetten were all either founded or fortified.

Strong forces thrusting forward from Mainz over the Wetterau and from Xanten through the valley of the Lippe, and supported by fleet operations on the coast of Holland and Friesland, were used against the German heartland intending to set the Roman frontier on the Elbe.

In CE 9, legions 17, 18, and 19 with their auxiliaries were destroyed in the Teutoburger Wald. Tiberius, faced with this loss of some 20,000 men, stopped operations in the Weser-Elbe region and, in CE 16, evacuated the military stations held beyond the Rhine.

Claudius linked the Danube frontier to the Rhine frontier. Gaps between the existing strong points, some built by Caligula, were filled with new works and a line was drawn from Freiburg in Breisgau to the Danube source. He stabilised the situation further by organising the province of Raetia covering the eastern part of Baden-Württemburg and western Bavaria.

Disturbances in Rome after the murder of Nero and leading to the succession of Vespasian gave the Germans on the lower Rhine the opportunity to destroy most of the Roman military bases on the Rhine as far south as Mainz.

Vespasian, ex Legate of the Legio II Augusta at Strassburg, reacted by ordering the Legate of the army in Germania Superior, Gnaeus Pinnarius Cornelius Clemens, to improve and develop the military communications.

A road was built from Strassburg to the new province of Raetia, passing through Rottweil to the Danube. This approach route was complemented by a road on the east bank of the Rhine linking the bridgehead opposite Mainz to Strassburg and stations further south.

A third route was developed from Mainz on the line of the Elisabethan Strasse and, following the old campaign route, through the Wetterau.