At first glance it is an astonishing fact that Rome did not conquer the Alpine region and the southern German foothills of the Alps before 15 B.C., although she had already seized power over northern Italy more than 200 years before. This was, however, perfectly in accord with the Roman conception of security and foreign policy: principally it required reaction to military threats, which could manifest themselves either in hostile attacks on Rome or on her allies and would thus provoke a military crisis, or simply in the form of a mere display of power by an alien nation, that is one which only potentially jeopardized Roman security interests. As a rule, Rome did not take the initiative in attempting to obtain possession of specific areas as a consequence of internal policy decisions, although exceptions occur with increasing frequency during the late Republic. As a matter of fact, there was no important power in the region of the Alps and their northern foothills on which Roman foreign policy might focus. Apart from raids by small bands, which could radiate from the prehistoric tribal world at any time and in any place, the Alpine tribes had never threatened northern Italy.

The peoples of the Alps were dissipated into a multitude of smaller tribes or valley dwellers, who were in fact partly interconnected by linguistic and cultural bonds, although not by significant socio-political ties. No larger tribal agglomerations (such as a single tribal unit of all Raetians) had developed and there had been no bigger settlements of an urban type except in the Vindelician area north of the Alps.