Roman Field Camp Construction and Engineering

As we have discussed in the past, the Romans were an extremely methodical race. While the Greeks were happy to contemplate the universe, the Romans were always in left brain overdrive --  breaking everything down into a structure that could be duplicated -- over and over again. So it was with field camp engineering.

I define field camp here as a short-term stopover for a field army traveling between two points. The destination could be permanent summer camp, permanent winter camp, or battle. Field camp construction is most impressive when you compare the effort involved with the short duration. You might imagine that at the end of a hard day of marching the commanders would pick out a clearing, pitch some tents, and call it a day. Not even close.

The marching army included an engineer unit which was dispatched to locate and prepare the camp site for the troops. They selected a site which would meet as many of the tactical requirements of the army as possible. The first and most important criteria was location. The engineers looked for a patch of even ground elevated from the surrounding area near a water supply. Terrain sloping away from the campsite would made attacks more difficult.

Once the site had been selected, surveyors precisely measured out the walls, roads, and sites for the structures to be placed in the camp.

 

This diagram shows the principal landmarks. The camp was formed by intersecting roads, with gates at the end of each. The main building of the camp was the Principia, located at the intersection of the two main roads.

The walls of the camp were designed to neutralize an attack. The first step in building them was to dig a trench six feet deep. When the trench was complete its sides were graded into a “V” to prevent an attacker from jumping across. The soil from the trench hole was then piled into a rampart frame of logs, making the total thickness of the rampart 3-5 meters. The top of the rampart was covered with palisades to produce a fence. Each legionnaire carried two 6 foot palisades in his kit which were tied together when placed.

Obstacles were never placed more than 40 meters from the defensive wall because javelins could not be hurled with accuracy beyond that distance.

 

Camp gates were designed to prevent the rush of an attack force. Techniques to prevent this usually involved a ditch in front of the gate or an angling the wall at the gate formed into a curve. Roads in the camp were 18 meters wide which was also the distance from the rampart to the first tent line.

Camp structures were sized according to importance of the occupant. The commander occupied the Praetorium (part of the principia), while the tribunes had their own barracks. The legionnaires slept in leather (calf or goat) tents designed to be waterproof. Each tent was ten feet square and housed eight men. Each century had eight tents for eighty men since sixteen were always on guard duty. Centurions had their own larger tent.

The camp was essentially a small city with wagon and horse parks, a hospital, washing and latrine facilities, and a cook tent. The granary was constructed to keep stored grain ventilated and raised off the ground.