The Roman army was one of the greatest forces of all time. At its finest point, it was nearly unconquerable due to the discipline and effective training of the soldiers, the speed at which new tactics were learned, and the organization of the soldiers.
From early times to the 3rd century A.D., the Roman army was based on its legions. A legion varied in strength from four thousand to six thousand men and was subdivided into ten cohorts. Its leader used the title of legatus. His staff officers were called tribuni. Senior non-commissioned officers were called centurions, who varied greatly in rank.
The soldiers of the legion were picked men. They were all Roman citizens and received a higher pay than the auxiliary troops, which were foreigners who served with the Roman army. A legion consisted of heavily armored infantry foot soldiers. The Roman infantry became a feared force, well disciplined and well trained. Their weapons were two javelins each and a short thrusting sword. Cavalry was supplied by the auxiliaries, second-line troops, and was organized mainly in units of 500 men.
During campaigns, the army was accompanied by seven specialists. One of them was the camp commandant, who was responsible for organizing the camp. The Romans were very careful about their camps, and no Roman army halted for a single night without digging trenches and fortifying the camp. Each soldier took part in establishing and striking the camp the next day.
Another specialist was the quaestor, whose duty was to look after all the money matters. Then there were the engineers, craftsmen, and artisans who were responsible for siege operations and the primitive Roman artillery.” This consisted of big catapults and complicated machines similar to crossbows, mainly used for hurling big rocks and stones at the walls of a defensive place. The engineers also had to build movable towers used in sieges.
The Roman soldiers went up inside these towers so that they could see over the walls of a fortified place and shoot their stones and arrows into it. The engineers also made the scaling ladders that were used for getting over walls.