Beating off An Assault
Here we see the Gallic relief force attempting to get through the layers of Roman defenses. Frst were the wood and iron stakes to get through. Next bramble bushes or tree branches. Then the ditch and finally the wall itself.
Wisely the tulmus (revalin or gate defense) is their main target. Roman gates were simple openings. The soldiers would form up in the opening.
To blunt an assault the Romans would erect a small wall just in front of the gateways. The men would man this small wall as others defended the openings and gateway on each side and rear.