The scale of certain military engineering feats, such as the construction of a double-wall of fortifications 30 mi long, in just 6 weeks to completely encircle the besieged city of Alesia in 52 B.C.E., is an example. Such military engineering feats would have been completely new, and probably bewildering and demoralizing, to the Gallic defenders. Vitruvius is the best known of these Roman army engineers, due to his writings surviving.

Examples of battles before