His light infantry consisted of argyraspides, with small silver-plated shields, and of numerous peltastœ, both of which troops were organized in semi-phalanxes of normally 8,192 men, being able to fight either in extended order or in line, like the hoplitae; and their phalanx often had the same success. The Macedonian cavalrv was composed of young Macedonian and Thessalian noblemen, with the addition subsequently of a body of horsemen from Greece proper. They were divided into squadrons (ilœ), of which the Macedonian nobility alone formed eight. They belonged to what we should call heavy cavalry; they wore a helmet and a cuirass with cuissarts of iron scales to protect the leg, and were armed with a long sword and pike. The horses, too, wore frontlets of iron. This class of cavalry, the cataphracti, received great attention both from Philip and Alexander; the latter used it for his decisive manoeuvre at Arbela, when he first beat and pursued one wing of the Persians, and then, passing behind their centre, fell upon the rear of the other wing. They charged in various formations: in line, in common rectangular column, in rhomboid or wedge-shaped column. The light cavalry had no defensive armor; it carried javelins and light short lances.

There was also a corps of aeroba-listœ or mounted archers. These troops served for outpost duty, patrols, reconnoitring, and ir-regular warfare generally. They were the con-tingents of Thracian and Illyrian tribes, which also furnished some few thousands of irregular infantry. A new arm invented by Alexander claims our attention from the circumstance that it has been imitated in modern times - the di-machœ, mounted troops expected to light either as cavalry or as infantry. The dragoons of the 16th and following centuries, as well as the light cavalry and mounted infantry of our own day, are complete counterparts to these ancient dimachae. We have no exact information as to the success with which the dimachae were used. The foregoing statement describes the composition of the army with which Alexander conquered the country between the Mediterranean, the Oxus, and the Sutlej. As to its strength at Arbela, it consisted of two large phalanxes of hoplitae (say 30,000 men), two semi-phalanxes of peltastae (16,000), 4,000 cavalry, and 6,000 irregular troops; in all about 56,000 men. At the Granicus, his force of all arms was 35,000 men, of whom 5,000 were cavalry. - The armies of the successors of Alexander show no improvements on his formations.

The introduction of elephants was but of short duration; when .terrified by fire, these animals were more formidable to their own troops than to the enemy. The later Greek armies, under the Achaean league, were formed partly on the Macedonian, partly on the Roman system. - Of the Carthaginian army we know no details; even the strength of the force with which Hannibal passed the Alps is disputed. - The Roman army presents us with the most perfect system of infantry tactics invented during the time when the use of gunpowder was unknown. It maintained the predominance of heavy infantry and compact bodies, but added to it mobility of the separate smaller bodies, the possibility of fighting in broken ground, the disposition of several lines one behind the other, partly as supports and reliefs, partly as a powerful reserve, and finally a system of training the single soldier which was even more to the purpose than that of Sparta. The Romans ac-cordingly overthrew every armament opposed to them, the Macedonian phalanx as well as the Numidian horse. In Rome every citizen from his 17th to his 45th or 50th year was liable to serve, unless he belonged to the lowest class, or had served in 20 campaigns on foot, or 10 campaigns as a horseman. Generally the younger men only were selected.

The drill of the sol-dier was very severe, and calculated to develop his bodily powers in every imaginable way. Running, jumping, vaulting, climbing, wrest-ling, swimming, first naked, then in full arma-ment, were largely practised, besides the regu-lar drill in the use of the arms and the various movements. Long marches in heavy marching order, every soldier carrying from 35 to 60 lbs., were kept up at the rate of four miles an hour.

The use of the intrenching tools, and the throwing up of intrenched camps in a short time, also formed part of the military education; and not only the recruit, but even the legions of veterans, had to undergo all these exercises in order to keep their bodies fresh and supple, and to remain inured to fatigue and want. In the best times of the republic there were generally two consular armies, each consisting of two legions and the contingents of the allies (in infantry of equal strength, cavalry double the strength of the Romans). The levy of the troops was made in a general assembly of the citizens at the capitol or on the Campus Martins; an equal number of men was taken from every tribe, which was again equally subdivided among the four legions, until the number was completed. Very often citizens, freed from service by age or their numerous campaigns, entered again as volunteers. The recruits were then sworn in and dismissed until required. When called in, the youngest and poorest were taken for the velites, the next in age and means for the hastati and principes, the oldest and wealthiest for the triarii.

Every legion counted 1,200 velites, 1,200 hastati, 1,200 principes, 600 triarii, and 300 horsemen (knights); in all, 4,500. The hastati, principes, and triarii were each divided into ten manipuli or companies, and an equal number of velites attached to each. The velites (ro-rarii, accensi, ferentarii) formed the light infantry of the legion, and stood on its wings along with the cavalry. The hastati formed the first, the principes the second line; they were originally armed with spears. The triarii formed the reserve, and were armed with the pilum, a short but extremely heavy and dangerous spear, which they threw into the front ranks of the enemy immediately before engaging him sword in hand. Every manipulus was commanded by a centurion, having a second centurion for his lieutenant. The centurions ranked through the whole of the legion, from the second centurion of the last or tenth manipulus of the hastati to the first centurion of the first manipulus of the triarii {primus pilus), who, in the absence of a superior officer, even took the command of the whole legion. Commonly, the primus pilus commanded all the triarii, the same as the primus princeps (first centurion of first manipulus of principes), all the principes and the primus hastatus, and all the hastati of the legion.