Princeps, Eques, Velites
The traditional Roman military formation from the time of the Republic’s founding (circa 500 b. c. e.) was modeled on the Greek hoplite phalanx. The weaponry of the Roman citizen soldier was also Greek: the short spear, round shield, helmet, armor, greaves, and sword. In the usual case of set-piece battles on level ground against armies using similar formations, the phalanx worked well enough. In uneven terrain, however, the phalanx could not maneuver. In the wars against the Samnites (340-290 b. c. e.) fought in the rugged Apennine hills, valleys, and glens the phalanx proved unworkable and very brittle to surprise attack. The wars with the wild Gauls demonstrated how easy it was for the highly mobile formations of the Gallic armies to envelop the open flanks of the phalanx and crush it from all sides once the cavalry was driven from the field. Given that Roman cavalry was never very good, driving it from the field prior to surrounding the phalanx was not usually difficult.
REPUBLICAN ROMAN ARMY ORGANIZATION
During and after the Samnite wars the phalanx legion was gradually replaced by the manipular legion. It was during this war that the Romans replaced their heavy Argive-type shields with the larger and lighter wooden scutum shield. The Romans also adopted the pilum from the Samnites. Both pieces of equipment remained standard Roman issue until the end of the Imperial period. The manipular legion was the basic fighting formation of the Roman army throughout the Punic Wars. However, Scipio Africanus found that the new legion was too fragile against the massed attacks of Hannibal’s heavy Spanish infantry. Scipio strengthened the maniples, increasing their numbers to 600 men. These new cohorts gradually replaced the maniples, and around 100 b. c. e., the Romans adopted the cohortal legion as their basic fighting formation.
The Roman army was also reorganized on the basis of age. The youngest, most agile, and least trained men (velites) served as light infantry. Armed with darts and small javelins, they acted as skirmishers. The front line of the legion was occupied by a second class of men, the hastati, who were somewhat older and more experienced. Armed with the sword, two pila, and the scutum shield, they formed the first line of heavy infantry. The center line comprised the best and most experienced veterans (principes). Averaging thirty years old, these were the battle-hardened veterans. The third line comprised older men (triarii) and constituted the last line of resistance. Armed with the long spear, they lent stability to the formation and in times of retreat remained in place and covered the passage of the other ranks through their lines.
The basic tactical unit of the new Roman army was the maniple (literally, “handfuls of men”), somewhat equivalent to the modern infantry company, with a strength of 120 men. Each maniple was divided vertically into two centuries equivalent to platoons of sixty to eighty men each. Originally, the centuries had comprised 100 men, but the number proved too large to be controlled effectively by a single centurion. The number was reduced to eighty, although the name “century,” meaning “one hundred,” was retained.
The key to the flexibility of the legion lay in the relationship between the maniples within each line and between the lines of heavy infantry. Each maniple deployed as a small, independent phalanx with a twenty-man front and a six-man depth. The spacing between each soldier allowed independent movement and fighting room within an area of five square yards. Each maniple was laterally separated from the next by twenty yards, a distance equal to the frontage of the maniple itself. In line the maniples were staggered, with the second and third lines covering the gaps in the lines to their front. Each line of infantry was separated from the next by an interval of 100 yards. The result was the quincunx, or checkerboard formation, that permitted maximum flexibility for each maniple and for each soldier within it.
ROMAN MILITARY TACTICS
Flexibility was increased by the relationship between the lines of infantry. If, after the first line engaged, it was unable to break the enemy formation or grew tired, it could retire in good order through the gaps left in the second line. The second line then moved to the front and continued to press the attack, while the first rank rested and regrouped. This maneuver could be repeated several times, with the effect that the Roman front line always comprised rested fighting men. This was an important advantage. Modern studies demonstrate that men engaged in phalanx close combat could sustain the effort no more than thirty minutes before collapsing from exhaustion. The triarii remained in place in the last rank, resting on one knee with their spears angled upward. The triarii represented the organic reserve of the legion, to be employed at the commander’s will.
The ability to pass through the lines of infantry in planned fashion offered another advantage. In most armies of the period, defeat of the front ranks often turned a battle into a rout. No army until the Romans had learned how to break contact and conduct a tactical retreat in good order. The manipular formation solved the problem. On command, the first line of infantry formed into close-order maniples, turned, and withdrew to the rear through the gaps left in the other two lines. The second rank followed. The triarri covered the retreat with their spears, and the velite light infantry deployed to the front to engage the enemy while the main body withdrew in good order. The ability to conduct an ordered retreat represented a major revolution in infantry tactics.
Tactical flexibility was further enhanced by the ability of each maniple to fight and maneuver independently. This flexibility allowed Roman commanders to make maximum use of the element of surprise. It was not unusual for a commander to position a few maniples in hidden positions, often at the flanks, or even to attempt to insert them to the rear of the enemy position. Once the main forces were engaged, these maniples could be brought into action, surprising the enemy with an attack from an entirely unexpected direction. Often, the sight of a few maniples marching on the main force from an unexpected direction was sufficient to cause the enemy to break. This capability provided the legions of Rome with a new tactical dimension of ground warfare.
The Roman soldier was the first soldier in history to fight within a combat formation while at the same time remaining somewhat independent of its movements as a unit. He was also the first soldier to rely primarily on the sword instead of the spear. The Roman sword of this period was a short slashing sword of Italian origin (antennae sword). During the Punic Wars the legions gradually adopted the famous gladius, a short sword incorporating many of the features of the Spanish falcata.
The gladius was twenty inches long and approximately three inches wide and was made of Spanish steel. It was stronger in composition than any existing sword, and because it would not bend or break, it provided a psychological advantage to the Roman soldier. To use it well required a high level of training and skill. The Roman army introduced military training programs in the use of the gladius, and in 100 b. c. e. the army began to be trained in the same methods used in the Roman gladiatorial schools. The gladius was primarily a stabbing weapon, and Roman soldiers were trained not to use it as a slashing weapon, the common method of sword use in most armies of the day. The shield parry, followed by a sharp under thrust to the chest, became the killing trademark of the Roman infantry. In the hands of the disciplined Roman soldier the gladius became the most destructive weapon of all time prior to the invention of the fi rearm. If the phalanx formations of past armies armed with the spear can be described as resembling spiked pincushions, then the Roman legion, with its reliance on the gladius, resembled a buzz saw.
A Roman legion had the strength of approximately 5,000 men and usually deployed with an allied counterpart of the same size and generally the same organization. The allied legion usually had a heavier cavalry section of approximately 600 horses, the Roman legion commonly possessing only 300 horses. The combined legions had 9,000-10,000 men. Two Roman legions and two allied legions under the same command comprised a consular army of 20,000 men deployed across a combat front of one and one-half miles.
The legion commander had a staff of professional officers who handled administrative, supply, medical, veterinary, and training matters. Combat command rested in the hands of six senior tribunes, two for each infantry line. Below them were the combat unit commanders of the maniples, sixty centurions, two for each maniple. The real combat leadership was provided by the centurions. Promotion of centurions through the ranks was based on demonstrated bravery and competence. The most noble soldiers of Rome were the First Centurions ( primus pilum, literally, “the first spear”) of the legions, and right to the end, they remained the best combat commanders the nation could field.