The migration plan of the Helvetian court and its implementation
If Caesar is serious in claiming surprise about the request of the Helvetii to pass
Geneva on their way to the territory of the flabby Gauls, there is some reason to scorn
Roman intelligence, something Caesar does not engage in. Does not such an entreprise
require a very long preparation?
Caesar understands this, he concisely describes it: in the three years before, excess food was cultivated and stored by the Helvetii to feed their entire population of 300 000 souls in the period between the start of the migration until the expected moment one would be settled again and have a new harvest in the new country.
Of course, a plan to leave the region en masse might make it attractive for some part of the population less loyal to the elite to lag behind and return. To prevent that, it was planned to burn all towns, all food and all cattle to be left behind.
After Caesar had chased them back to their original place, using his legions as shepherd dogs, one third of the Helvetians, 100 000 souls, was left, the toughest of the tough, of course, and from then on, those remaining Helvetians consistently chose to fight the Germans rather than the Romans.