Army strenghts

[konny]

Napoleon said that according to the movements, operations and combats described by Caesar the forces at Alesia must have been of about equal size. He was of course no historian but one of the most reliable authorities in military questions. Since the Romans had some 70,000 men in the field the Gauls can be estimated of something between 50,000 and 100,000 men.

All other figures in Caesar seem to be pure fantasy too; as long as we take the events reported for granted and do not assume that all his opponents (professional militairs themselves) were idiots on the tactical field. As long as we assume that Caesar and the Romans usually fought their battles with numerical superiority we also do no longer need to search for explanations what made the Legionars supermen, worth ten battleharded Gauls or Germanics each.

On the logistical topic: 19th Century militairs calculated 1 meter of space per every man on the march. That would make 10,000 men a column of 10 kms. An amry of 100,000 men on the march would stretch for 100 kms and would by this need 3 days to gather on a spot. This effect can be reduced by marching them on parrallel roads. But as long as you cannot assume a decent system of good roads (and for most of ancient Europe you can't) some armies that are reported in the sources simply can't have existed in that size because there was not enough room to line them up on the existing roads and move them forward a single step.