It may fairly be argued that the eight years from 58 BC to 51 BC were the most decisive in the history of France, and indeed of Western civilization. In the course of those eight years, Julius Caesar conquered most of Gaul, a region corresponding roughly to modern France, plus much of present-day Belgium and Switzerland. In the process, he transformed what had been essentially a Mediterranean empire and civilization into one that extended into the heart of continental Western Europe.
The following discussion will be devoted to the strategic and tactical dimensions of Caesar's conquest of Gaul, with the central theme being the ways in which Caesar's methods employed established Roman methods in new ways to solve problems that were new to Roman experience. The exceptional nature of Caesar's conquest in Roman history will first be outlined, followed by a brief sketch of the relationship of Caesar's political strategy in Gaul to that previously employed by the Roman Republic. More extensive treatment will then be given to the Roman method of warfare and the employment of those methods by Caesar, with special attention to the difference between the military problems solved by Caesar to those for which the legions had originally been designed.
Julius Caesar did not set out to conquer Gaul. He was there in the first place due to the vagaries of Roman domestic politics, and throughout his campaigns he had one eye on Rome--his account of the Gallic War was indeed largely an exercise in propaganda, designed to keep him in the public eye and lay the groundwork for continued involvement in Roman politics. The resulting conquest was very much the exception in Roman history, and had it not taken place, it is entirely plausible, even probable, that later Romans would have been content to establish only a defensive limes in southern Gaul to protect their existing province along the Mediterranean coast.
Caesar adapted long-est...