The army of Alexander was an instrument which he inherited from his
father Philip. Its core was composed of the Macedonian peasantry who
served on foot in heavy armour ("the Foot-companions" [Greek:
pezetairoi]). They formed the phalanx, and were divided into 6
brigades ([Greek: taxeis]), probably on the territorial system. Their
distinctive arm was the great Macedonian pike (_sarissa_), some 14 ft.
long, of further reach than the ordinary Greek spear. They were
normally drawn up in more open order than the heavy Greek phalanx, and
possessed thereby a mobility and elasticity in which the latter was
fatally deficient. Reckoning 1,500 to each brigade, we got a total for
the phalanx of 9,000 men. Of higher rank than the _pezetaeri_ were the
royal foot-guards ([Greek: basilikoi hypaspistai]), some 3,000 in
number, more lightly armed, and distinguished (at any rate at the time
of Alexander's death) by silver shields. Of these 1,000 constituted
the royal corps ([Greek: to agema to basilikou]). The Macedonian
cavalry was recruited from a higher grade of society than the
infantry, the _petite noblesse_ of the nation. They bore by old custom
the name of the king's Companions ([Greek: hetairoi]), and were
distributed into 8 territorial squadrons ([Greek: ilai]) of probably
some 250 men each, making a normal total of 2,000. In the cavalry also
the most privileged squadron bore the name of the _agema_. The ruder
peoples which were neighbors to the Macedonians (Paeonians, Agrianes,
Thracians) furnished contingents of light cavalry and javelineers
([Greek: akontistai]). From the Thessalians the Macedonian king, as
overlord, drew some thousand excellent troopers. The rest of
Alexander's army was composed of Greeks, not formally his subjects.
These served partly as mercenaries, partly in contingents contributed
by the states in virtue of their alliance. According to Diodorus
(xvii. 17, 3) at the time of Alexander's passage into Asia, the
mercenaries numbered 5,000, and the troops of the alliance 7,000 foot
and 600 horse. All these numbers take no account of the troops left
behind in Macedonia, 12,000 foot and 1,500 horse, according to
Diodorus. When Alexander was lord of Asia, innovations followed in the
army. Already in 330 at Persepolis, the command went forth that 30,000
young Asiatics were to be trained as Macedonian soldiers (the
_epigoni_, Arr. vii., 6, 1). Contingents of the fine Bactrian cavalry
followed Alexander into India. Persian nobles were admitted into the
_agema_ of the Macedonian cavalry. A far more radical remodelling of
the army was undertaken at Babylon in 323, by which the old phalanx
system was to be given up for one in which the unit was to be composed
of Macedonians with pikes and Asiatics with missile arms in
combination--a change calculated to be momentous both from a military
point of view in the coming wars, and from a political, in the close
fusion of Europeans and Asiatics. The death of Alexander interrupted
the scheme, and his successors reverted to the older system. In the
wars of Alexander the phalanx was never the most active arm; Alexander
delivered his telling attacks with his cavalry, whereas the
slow-moving phalanx held rather the position of a reserve, and was
brought up to complete a victory when the cavalry charges had already
taken effect. Apart from the pitched battles, the warfare of Alexander
was largely hill-fighting, in which the _hypaspistae_ took the
principal part, and the contingents of light-armed hillmen from the
Balkan region did excellent service.
For Alexander's army and tactics, beside the regular histories
(Droysen, Niese, Beloch, Kaerst), see D. G. Hogarth, _Journal of
Philol._, xvii. 1 seq. (corrected at some points in his _Philip and
Alexander_).