>>12605882The Battle of Alesia would have been a better example to use for Caesar.
Caesar has just been defeated (indecisively) at Gergovia by the Gauls, who then retreat to the fortified and highly defensible hilltop settlement of Alesia. Caesar pursues, and is now faced with an impossible tactical situation. If he attacks, he will be doing so uphill, against a numerically superior force in a favorable position. The Gaulish leader, Vercingetorix, recently sent for reinforcements, so if Caesar takes too long in figuring out how to proceed, he will be caught between two armies.
So, what does Caesar do? He decides to besiege Alesia. This is far outside of the military orthodoxy of the time. Traditionally, holding a two-to-one advantage over the defending force was considered adequate for a siege, with three-to-one being ideal. And it goes without saying that your logistical situation must not be in doubt. Yet here Caesar was with a numerically inferior force deep in enemy territory. Previously friendly Gaulish tribes which had supplied him with food had since turned hostile and joined Vercingetorix's revolt. Despite all this, he decided to besiege the fort.
He has his men construct 11,000 feet worth of high walls with guard towers at the base of the hill, closing off all avenues of supply, communication, and retreat for the defending force, and then turns right around and constructs an even longer wall facing in the other direction in anticipation of an attack by Vercingetorix's reinforcements. The walls were in turn reinforced by trenches, spike traps, and sharpened stakes at the base of the walls.
Caesar's force completed these fortifications in a matter of weeks, and cleared significant portions the local woods in the process. His 60,000 men held off nearly 200,000 Gauls. Vercingetorix surrendered soon after.
