LEGION (Lat. kg/a, properly a 'levy,' 'choice,' from loge e, 'to choose,' 'select,' Gk. V-yeev,itytin. to choose). The tactical unit of the Roman army. In early Rome, the army con sisted ipso facto of all the citizens. i.e. patri cians, capable of hearing arms. Thus it was an irregular force that could be summoned to com bat in time of need by the chief. Romulus is said to have organized a force consisting of 3000 Waite's, or armed infantrymen, and 300 ce/creR, or horsemen (knights) ; these were furnished in equal numbers (one thousand militcs and one hundred (Titres) by each of the three tribes, Ramnes. Tities, and Luceres, into which the citi zens were divided. and commanded severally by the tribunes militum and the tribonus relnrum.
It was King Servius Tullius, however, accord ing to the tradition of the ancients, who first or ganized the army on a substantial military basis, In accordance with the democratic reforms of the time, the warriors were not drawn exclusive ly from the patriciate; the lower classes also, or prokturii, were permitted to bear arms. The iuniores, or younger men. from seventeen to forty-six, formed the backbone of the army, and bore. the brunt of actual fighting in the field; the seniores. elder men, from forty-six to sixty, de fended the. city. and took the field in times of pressing need. They fought in the form of the phalanx. or solid body, without ally regular di vision into battalions, except on the basis of age and rank described above: a system that was maintained until the beginning of the fourth century P.c., when a new reform is said to have been organized by Camillus ( n.c. 3901. This new system had for its basis the /(/io, or army corps. two of which formed the txtreitas eon safaris. or consular army. The legion was com manded by six tribuni militUnl, always mem bers of the nobility. who took turns, by the (lay or the month, in the actual command. Legions were always enrolled for a single year's campaign, and dismissed at the end of the season. The war riors were compelled to furnish their own equip ment, except that the proletarii were equipped by the State. With the gradual conquest of Italy, however, and the numerous wars with nations beyond the sea. this system of annual citizen soldiery became impossible, and war tended to become a profession.
The army. as organized on the legionary sys tem of the Republic, was divided as follows: the ler(ion consisted normally of 4200 infantry and 300 cavalry: the infantry body (asIde from the proittarii) was divided into thirty maniples, and •ash maniple was subdivided into two centuries, or 'companies.' But there was also a division ac cording to age and experience. Each legion had 120U ha8tati, or younger men, forming the first line in battle, 1200 prineipcs, men of riper years, and 600 triarii, or veterans; and this was the legion proper, as divided into maniples and cen turies. They were armed with bronze helmets with plumes (cassis), cuirass (iorica), greaves (ocretr), a long semi-cylindrical shield (seatum), and a short, pointed. double-edged sword (glu dius). The hastati and principes carried also each two pil«, or long, heavy javelins, while the triarii bore lighter lances. In addition to tho above, each legion had 1200 rctitcs, light-armed troops drawn from the prolctarii, armed with leather helmet (galea), round shield (parma), and short sword (gladius). The 300 horsemen
(equines) attached to the legion were divided into ten tenant of thirty horse each, each tu•ma under the command of three decurions. Each infantry maniple was captained by a centurion, and had its own standard, while the legion as a whole had its eagle (alluila legionaria). A new reform in army organization was due to Gains Marius at the each of the second century n.c. The census or position according to social rank wholly ceased to be regarded. The Italian allies of Rome were admitted to the legions. The class of rclites was abolished, and the cavalry was no Niger made Imp exclusively of Roman cquites. The army was now a permanent body, and twenty years was the usual term of service. An impor tant change was effected also in the internal organization of the legion. Its tactical division was no longer the maniple, but the cohort (colors). The three lines were assimilated, and the legion was divided into ten cohorts, each consisting of three maniples, or six centuries. At the !OM' time the effective strength of the legion was increased, but during the civil wars the actual number of men varied with the exigencies and possibilities of the case. normal strength of the cohort was soon raised to (100. making a legion of 6000 men, besides aux iliary troops and cavalry drawn from the bar barian subjects and allies of Rome. In battle, the legion was arranged in two lines of five cohorts each; but Ctesar altered the formation to three lines. of four, three, and three cohorts, respectively. The chief centurion of the triarii, or veterans, known as Kim us pil us, was the ranking officer of the legion, but the respon sibility of command was vested in the legates lcgionis, or lieutenant-general. while the six iribuni militum remained a sort of honorary staff of young nobles, who used this irrespon sible form of military service as a first step in their public career, but were actually rather a nuisance in the army.
When the battle of Actium (n.c. 31) left Octavius in smile control of the Roman world, there were remnants of fifty legions tinder his command. In B.C. 27 he effected a thorough reorganization of the Roman armies, reducing the total number of legions to twenty-three, to which he added two new ones about n.c. 5. Under the Empire, when whole legions were annihilated in war, either they were newly recruited or the name was dropped. The number of legions, how ever, gradually increased. Claudius added a new one after his conquest of Britain; Nero created three more; Galba, one; and so on until under Septimius Severus there was a total of thirty-three legions, which remained the full number until the reign of Diocletian. Under the late Empire, the quota of men to the legion was reduced, but the number of legions was vastly increased. In the fotirth century there were more than 175 legions in the field.
The legions of the Empire were distinguished by numbers and names, as lcgio l7II Augusta, legio XII •ulminato. icgio ..Y1' Anollinaris. Titles were sometimes bestowed by the Emperors, as special marks of honor, as pie (loyal), vim/ex (avenging). Sometimes they were derived from the name of the reigning Emperor, as S'ercriana, Antoniniana, and often from the place of service, as Italica, Jlaredonica. On the legions of the Empire, consult Pfitzner, Geschichte der ra mischen, KaiscrIcgioncn (Leipzig. 1881).