Philip barely existed in the Hellenic world, also became a serious component of warfare during the reign of that monarch and especially in that of his son. Hellenistic naval warfare might be seen as beginning with the Carthaginians and the creation of the quadrireme, as claimed by Aristotle (Pliny NH 7. 207), or perhaps with Alexander in his siege of Tyre (Curt. 4.3.14), bringing to a close the centuries of domination of the trireme. But it is in infantry warfare that Philip’s and Alexander’s contributions are most noted. Philip introduced a whole new heavy infantryman equipped with a pike instead of the stabbing spear that had dominated land warfare in the Western world for more than two centuries. Along with his son Alexander, he enhanced what is today commonly called “Combined Arms,” the integration of differently equipped military units, into a complementary force. Where, prior to these commanders, it was the heavy infantry that principally fought with light-armed troops most often engaging one another as skirmishers and cavalry either to defend the vulnerable flanks of these heavy infantry units or to hunt down fleeing infantrymen. The two Macedonian kings and especially the latter coordinated many different arms representing the flower of land forces both from the Greek world and, with Alexander, that of Asia. After Alexander’s death, changes emerged over time that diminished the skillful use of combined arms. Much of this was due not so much to deliberate changes in tactics but to the political changes that saw the breakup of Alexander’s empire and the emergence of a number of competing states.
Philip II
To understand the dramatic change in warfare, and in civilization itself, it is necessary to begin with those reforms initiated by Philip II. He transformed warfare by making the most of the resources available to him and saving Macedon from what might have been its extinction as a political entity. His accession to the throne in 359 came on the death of his brother, the former king, on a battlefield along with 4,000 Macedonian troops. Not the most auspicious of beginnings. The Illyrian victors from the northwest part of the Greek peninsula were now encamped in Macedon with much of the northern and western areas of the country either occupied or allied with the invaders. In a little more than two decades, Philip brought Macedon from seeming ruin to the most powerful state in the eastern Mediterranean. Much of this transformation resulted from his revolutionizing the instruments of war.
Prior to Philip, Macedon had been a land ruled ostensibly by an autocrat whose theoretical powers included control of foreign policy, the military, the state religion, and natural and human resources. In reality these powers were much curtailed. Most of the highland regions—Upper Macedonia—were under the control of local aristocratic families who paid only occasional lip service to the authority of the lowland king, and at Philip’s accession to the throne, these were either allied with or subjects of the Illyrians. Even in the lowland plain, powerful aristocrats controlled the localities. The king had no true bureaucracy, but relied on these aristocrats to perform many of the functions of government. They were his military commanders and his administrators. They also made up the Macedonian cavalry, which was the best in the Western world. These aristocrats were the king’s Hetairoi, his companions. With these individuals the king enjoyed a close personal relationship and shared his leisure activities. This relationship with the aristocracy was one that reminds many modern historians of the society described in Homer’s Iliad.1 While the Macedonian cavalry was a force to be reckoned with, unfortunately, the same could not be said of the Macedonian infantry, which was lightly armed, ill trained, and mostly under the control of their aristocratic officers, who were also their civilian overlords. The vast majority of the population were either tenant farmers or dependent pastoralists bound to some local aristocrat.2 This situation was quite different from that of the Greek communities to the east and south whose infantries were based on long-established traditions of middle-class heavy infantry, the so-called hoplites who dominated the Classical Age. These soldiers wore bronze breastplates and greaves, carried a circular, three-foot in diameter, shield, and a roughly seven-foot long thrusting spear. They fought typically in a compact unit, the phalanx. Cavalry and light-armed troops played a secondary role, protecting the flanks and rear of these formations, and often pursuing the defeated after the battle was won. Macedonia, then, at the start of Philip’s reign, was disunited with much of the interior dominated by a powerful, land-holding aristocracy and the coast by independent Greek cities, and, at the time of his accession, suffering foreign occupation.
To drive out the Illyrians, Philip created the famous Macedonian phalanx, which would dominate Western warfare for almost two centuries. Faced with a population that could not afford the hoplite panoply and insufficient royal revenues, Philip was forced to change the very nature of the infantry panoply and tactics. He also had to deal with a Macedonian army that had been virtually annihilated in the recent battle. Whereas the hoplites were previously the offensive key to victory, Philip made his new infantry primarily a defensive force. In his new army, the infantryman was equipped with a 15-foot pike (the sarissa),3 a 2-foot diameter shield hung from the neck and shoulder, and little else in the way of defensive armor. This new panoply was cheaper and the soldier required far less training. Over time, the pikes lengthened so that in the later Hellenistic period they might be as long as 24 feet (Polyb. 18.29.2). Such formations of tightly packed pikes could easily defend against frontal assaults by either hoplites or cavalry. These troops resembled the later Swiss pikemen of the early modern era, a similarity noted by Nicolo Machiavelli.4 The inspiration for this innovation by the new Macedonian king is unclear. Modern historians cite earlier experiments with longer spears by other commanders, or their occasional use by neighboring tribal peoples, but it is also possible that Philip simply adopted and adapted the long spears traditionally used in hunting.5 Whatever the inspiration, it was Philip who realized the potential and brought it to fruition.
While others may have seen the potential, they lacked the means to make a pike phalanx effective.6 To a great extent invulnerable to frontal attacks on level ground, a pike phalanx was incredibly vulnerable on the flanks and rear, and found it difficult to maintain its impenetrable front on broken ground (Polyb. 18.30.11, 31.5–6). In order to compensate for the weaknesses in this new infantry formation the Macedonian king maintained a force of infantry guards trained both as pike bearers and as hoplites, initially called the Pezhetairoi and later the Hypaspists.7 These troops represented a standing, national, professional force, and typically occupied the right wing. When used as hoplites, they gave more flexibility on the wing, most often engaging the enemy infantry first. Beginning as a royal guard, they likely numbered only a few hundred. Their eventual strength was 3000. More mobile than the “typical” Macedonian phalangite, they were regularly equipped for hand-to-hand warfare. The most significant change for these elite troops was that the hoplite’s heavy metal breastplate had been replaced with one of linen or leather, reinforced with iron plates. As Alexander marched deeper into Asia, more units were equipped in the manner of the Hypaspists. This was especially the case after the dismissal of the allied Greek heavy infantry of hoplites (Arr. Anab. 3.19.6; cf. Diod. Sic. 17.17.3). It has also been recently argued that as Alexander continued into Asia he required more of these modified hoplite units, and many of his sarissa battalions were converted, and acquired the name of asthetairoi.8
But the key to Philip’s new army was that he possessed a great advantage over those who may have experimented with the pike earlier—the native cavalry of Macedonia. Not only would the cavalry protect the vulnerable phalanx but, in Philip’s new model army, it would become the principal attacking force. With the Macedonian infantry occupying the full attention of the enemy, the cavalry, in what has been described as the “hammer and anvil” tactic, would probe for weaknesses that could then be exploited for victory. The infantry became the anvil on which the hammer of the cavalry would smash the enemy. With this new army, Philip subdued his enemies and his son Alexander conquered the Persian Empire. Macedonian cavalry was so expert that, in a wedge formation, it could punch through a weakened or gapped infantry line.9
This use of what is currently referred to as “Combined Arms” was augmented further by Philip and especially by his son Alexander with the incorporation of light-armed infantry and cavalry. In addition to the heavy infantry units, Philip’s new model army included archers, slingers, and significant numbers of light-armed infantry, the peltasts.10