Rome’s Legions

The constitution of the Imperial legion may be described in a few words.

Continuing Roman Empire’s Extent and Defense,
our selection from The History of the Decline and Fall of the Roman Empire by Edward Gibbon published in 1776. The selection is presented in nine easy 5-minute installments. For works benefiting from the latest research see the “More information” section at the bottom of these pages.

Previously in Roman Empire’s Extent and Defense.

Time: 2nd. Century (100-200) AD

And yet so sensible were the Romans of the imperfection of valor without skill and practice, that, in their language, the name of an army was borrowed from the word which signified exercise. Military exercises were the important and unremitted object of their discipline. The recruits and young soldiers were constantly trained, both in the morning and in the evening, nor was age or knowledge allowed to excuse the veterans from the daily repetition of what they had completely learnt. Large sheds were erected in the winter-quarters of the troops, that their useful labors might not receive any interruption from the most tempestuous weather; and it was carefully observed, that the arms destined to this imitation of war, should be of double the weight which was required in real action. It is not the purpose of this work to enter into any minute description of the Roman exercises. We shall only remark, that they comprehended whatever could add strength to the body, activity to the limbs, or grace to the motions. The soldiers were diligently instructed to march, to run, to leap, to swim, to carry heavy burdens, to handle every species of arms that was used either for offence or for defense, either in distant engagement or in a closer onset; to form a variety of evolutions; and to move to the sound of flutes in the Pyrrhic or martial dance. In the midst of peace, the Roman troops familiarized themselves with the practice of war; and it is prettily remarked by an ancient historian who had fought against them, that the effusion of blood was the only circumstance which distinguished a field of battle from a field of exercise.* It was the policy of the ablest generals, and even of the emperors themselves, to encourage these military studies by their presence and example; and we are informed that Hadrian, as well as Trajan, frequently condescended to instruct the unexperienced soldiers, to reward the diligent, and sometimes to dispute with them the prize of superior strength or dexterity. Under the reigns of those princes, the science of tactics was cultivated with success; and as long as the empire retained any vigor, their military instructions were respected as the most perfect model of Roman discipline.

Nine centuries of war had gradually introduced into the service many alterations and improvements. The legions, as they are described by Polybius, in the time of the Punic wars, differed very materially from those which achieved the victories of Caesar, or defended the monarchy of Hadrian and the Antonines. The constitution of the Imperial legion may be described in a few words. The heavy-armed infantry, which composed its principal strength, was divided into ten cohorts, and fifty-five companies, under the orders of a correspondent number of tribunes and centurions. The first cohort, which always claimed the post of honor and the custody of the eagle, was formed of eleven hundred and five soldiers, the most approved for valor and fidelity. The remaining nine cohorts consisted each of five hundred and fifty-five; and the whole body of legionary infantry amounted to six thousand one hundred men. Their arms were uniform, and admirably adapted to the nature of their service: an open helmet, with a lofty crest; a breastplate, or coat of mail; greaves on their legs, and an ample buckler on their left arm. The buckler was of an oblong and concave figure, four feet in length, and two and a half in breadth, framed of a light wood, covered with a bull’s hide, and strongly guarded with plates of brass. Besides a lighter spear, the legionary soldier grasped in his right hand the formidable pilum, a ponderous javelin, whose utmost length was about six feet, and which was terminated by a massy triangular point of steel of eighteen inches. This instrument was indeed much inferior to our modern firearms; since it was exhausted by a single discharge, at the distance of only ten or twelve paces. Yet when it was launched by a firm and skillful hand, there was not any cavalry that durst venture within its reach, nor any shield or corselet that could sustain the impetuosity of its weight. As soon as the Roman had darted his pilum, he drew his sword, and rushed forwards to close with the enemy. His sword was a short well-tempered Spanish blade, that carried a double edge, and was alike suited to the purpose of striking or of pushing; but the soldier was always instructed to prefer the latter use of his weapon, as his own body remained less exposed, whilst he inflicted a more dangerous wound on his adversary. The legion was usually drawn up eight deep; and the regular distance of three feet was left between the files as well as ranks. A body of troops, habituated to preserve this open order, in a long front and a rapid charge, found themselves prepared to execute every disposition which the circumstances of war, or the skill of their leader, might suggest. The soldier possessed a free space for his arms and motions, and sufficient intervals were allowed, through which seasonable reinforcements might be introduced to the relief of the exhausted combatants. The tactics of the Greeks and Macedonians were formed on very different principles. The strength of the phalanx depended on sixteen ranks of long pikes, wedged together in the closest array. But it was soon discovered by reflection, as well as by the event, that the strength of the phalanx was unable to contend with the activity of the legion.

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