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.