The latter naturally took the highest rank of the whole Macedonian army, and bore the name of the “guards” or the “king’s guards.” It consisted of eight ilai or squadrons, which were called indifferently by the names of their districts or of their ilarchoi (colonels). That under Clitus called the royal ile, held the first rank among the Macedonian knighthood and formed the agema or royal guard. Besides these knights from Macedonia and Thessaly, there were six hundred more Greek horsemen in the army; they were usually attached to the Thessalian squadron, and seemed to have been similarly armed and drilled. They were commanded by Philip, the son of Menelaus.
Next in rank comes that peculiarly Macedonian body, the hypaspists. The Athenians under Iphicrates had already instituted, under the name of peltasts, a corps with linen corslets, and lighter shields and longer swords than those carried by the hoplites, in order to have a force swifter in attack than the latter and heavier than the light-armed troops. This new kind of corps was received with great approval in Macedonia; the soldier of the phalanx was too heavily armed for service about the person of the king, the light armed soldier was neither dignified nor serviceable enough. This intermediate force was selected for the purpose, and received the name of hypaspists from the long shield, the aspis, as it was called, which they had adopted from the phalanx. This force was of enormous value in a war against Asiatic tribes, for the lie of the land hampered only too often the full use of the phalanx, and it was often essential to attempt surprises, quick marches, and strokes of all sorts for which the phalanx was not sufficiently mobile nor the light troops sufficiently steady. For occupying heights, forcing the passage of rivers, and supporting and following up cavalry charges, these hypaspists were admirably adapted. Their numbers amounted to six thousand men. The whole corps was led by Nicanor, whose brother, Philotas, commanded the knights of the guard, and whose father, Parmenion, is described as general of the phalanxes. The first chiliarchy was that of Seleucus; it bore the title of “royal hypaspists,” and in its ranks the sons of noble families saw their first military service as pages of the king. The second bore the title of “royal escort of hypaspists,” and kept guard over the king’s tent.
THE LIGHT TROOPS
The light troops of the Macedonian army were of peculiar importance. They came from the countries of the Odrysians, Triballians, Illyrians, Agrians, and from upper Macedonia; they were armed with their national weapons of offence and defence, and exercised by the hunting and raiding to which they were accustomed at home and the countless petty wars of their chieftains, they were of extreme value in skirmishing, covering the line of march, and for all the purposes served by Pandours, Croats, and Highlanders in modern warfare. The most famous among them are the Agrian chasseurs and the Macedonian archers, who may have formed together a corps of about two thousand men. There is hardly a battle in which they do not play a prominent part, and the devotion with which they fought is testified by the circumstance that the post of toxarch had to be filled afresh three times in one year. At the opening of the campaign it was held by Clearchus, Attalus being in command of the Agrianians. The strength of the other light troops, usually known by the general designation of Thracians, was five thousand men, under the command of the Thracian prince Sitalces.
It is obvious that in these troops Alexander brought into use a strategic element hitherto practically non-existent. At all events, the light troops of the Greek armies before his time had been of no great importance, either by numbers or by the uses which they served; nor had they escaped a certain amount of contempt—a natural result of the Greek preference for sword-play, rendered more natural by the fact that their light infantry was composed partly of the off-scouring of the people and partly of barbarian mercenaries. There now appeared on the scene light troops whose national characteristics proved advantageous in this particular kind of fighting, and whose strength and glory lay in those arts of surprise, alarm, and retreat in apparent confusion, which seemed purposeless and questionable to Greek warriors. The famous Spartan general Brasidas himself confessed that the onset of these tribes—with their loud war-cries and the menacing waving of their weapons—had in it something alarming; their capricious transition from attack to flight, and from disorder to pursuit something terrible, against which nothing but the strict discipline of a Hellenic regiment could make it proof. As a matter of fact, these bands were able to fulfil their object to perfection because, being light troops by nature, they needed, when combined with the serried masses of the army, to be used for no purpose except that for which they were naturally fit.
The fundamental principle of the battle array of the Macedonian army was as follows. The army formed two wings, the left under Parmenion, and the right (which usually made the main attack) under Alexander. The infantry of both wings, four divisions of the phalanxes on the right and two, with the corps of hypaspists, on the left, formed the main line, to which were attached the light and heavy cavalry and the light infantry; the invariable order being that the Macedonian guards were on the right, with the Pæonian cavalry and skirmishers, the Agrianian chasseurs and the archers; and the Thessalian guards on the left, with the Greek cavalry, Agathon’s Odrysian Thracians, and, lastly, the light infantry, which was often detached from the fighting-line to protect the camp and baggage. In the closest formation, when the phalanx was covered by its shields and stood sixteen deep, and the cavalry eight deep, the line of battle required a plain of at least half a mile in breadth to deploy in, as a rule the phalanxes alone forming a line nearly five thousand paces long.
Such was the army with which Alexander proposed to conquer the East. Though relatively small in numbers it had every prospect of success by reason of its organisation, the excellent discipline of the several corps, the moral force of all, and finally, the personal character of the king and his generals. The Persian empire was not in a position to offer resistance; in its extent, the condition of its subject races, and the inefficiency of its government it contained the elements of its inevitable ruin.