ABSTRACT
The safety of the empire demanded that he should push the frontiers well back, but distant frontiers involved entrusting armies to men far from the eye of the Princeps, and long frontiers required more men and expense. Augustus therefore tried to establish as economical a frontier system as was consistent with safety, and at the same time to create an army that would guard it adequately while remaining loyal to himself. The army was permanently stationed in the provinces where it was most needed, and in relation to the length of the frontiers to be guarded, it was none too large. In order to secure Cisalpine Gaul Augustus decided that it was necessary to conquer the whole Alpine range and by reducing the districts of Raetia and Noricum to advance the frontier to the Danube from Lake Constance to Vienna. Augustus continued the Republican method of working through existing provincial communities, whether cities or tribes.
