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Philip II of Macedon: Military Mastermind Who Conquered Greece


In the 4th century BC, a military revolution occurred in ancient Greece that would change the face of warfare. At its center was Philip II, king of Macedonia from 359 to 336 BC. Through a sweeping program of reform, he transformed a feudal levy into the most sophisticated army of the age. This new war machine powered Macedonia‘s rise from a backwater kingdom to the hegemon of Greece, setting the stage for his son Alexander the Great‘s conquest of Persia.

Philip‘s military genius lay in his ability to synthesize cutting-edge weaponry, innovative tactics, and an efficiently organized military system into a cohesive whole. The core of his tactical reforms was the introduction of the sarissa infantry pike, which when wielded in a novel phalanx formation, proved virtually unbeatable. Coupled with a formidable heavy cavalry arm and state-of-the-art siege engines, Philip forged a combined-arms force without parallel. This article will explore the radical military innovations that earned Philip his place among history‘s preeminent generals.

The Macedonian Army Before Philip

To understand the scale of Philip‘s achievement, we must first examine the state of Macedonia‘s army before his reign. Our main source is the historian Thucydides, who paints a grim picture. He describes the Macedonians as "not even a people, but rather a mob, absolutely without discipline" [1]. Archaeological evidence bears this out – graves from the period contain a hodgepodge of weapons and armor, indicating a lack of standardization [2].

The Macedonian levy was essentially a feudal army, with men called up to serve their king as needed. They were chiefly light infantry – slingers, javelinmen, and archers – with only a small core of elite hoplites. This force was no match for the armies of Macedonia‘s neighbors, as evidenced by a string of defeats in the early 4th century BC that saw much of the kingdom overrun.

Philip‘s Early Career and Reforms

This was the situation the 23-year-old Philip inherited in 359 BC. But he was no stranger to war. As a youth, Philip was held hostage in Thebes, where he observed the tactical genius of Epaminondas, the general who had crushed the hitherto invincible Spartans at Leuctra with an innovative new battle formation [3]. Philip also studied the reforms of the Athenian general Iphicrates, who experimented with lightening his infantry‘s equipment to increase mobility.

Upon assuming the throne, Philip instituted a sweeping military reform program. His first act was to organize the kingdom into four military districts, each providing a professional standing army [4]. Philip created a formal chain of command, with officers appointed based on merit rather than birth. He also instituted rigorous training, drilling his men in marching and rapidly forming up for battle.

But the centerpiece of Philip‘s tactical reforms was a new kind of infantry, armed with a revolutionary pike called the sarissa. The sarissa was a massive spear, measuring between 4 and 6 meters long [5]. Its great length meant it had to be wielded with two hands, so Philip equipped his sarissa-bearers, called phalangites, with a smaller shield called a pelta that could be slung over the shoulder. He also lightened their armor, trading the hoplite‘s heavy bronze cuirass for a lighter linen corselet [6].

The Macedonian Phalanx

In battle, Philip‘s phalangites fought in a rectangular formation typically 16 men deep [7]. The first five ranks would lower their sarissas horizontally, creating a bristling wall of spearpoints. The remaining ranks angled their pikes upwards, forming a layered defense against missiles. With four sarissa points projecting in front of the first rank, the phalanx presented an impenetrable wall of pikes to its foes.

The Macedonian phalanx was a devastating offensive force. A massed phalanx charge could sweep away virtually any foe, as opponents armed with shorter weapons simply couldn‘t reach the phalangites to strike a blow [8]. Even the most formidable infantry of the day, like the Theban Sacred Band, crumbled against the phalanx‘s ruthless killing power.

However, the phalanx did have significant weaknesses. Its strength lay in its cohesion – if its rigid formation was disrupted, by rough terrain or an attack on the flanks or rear, the phalangites became extremely vulnerable [9]. The sarissa was ill-suited for individual combat, and the phalangites‘ light armor left them at a disadvantage in close-quarters fighting.

Elite Units and Cavalry

To offset these weaknesses, Philip created elite infantry units to fight alongside the phalanx. The hypaspists, meaning "shield-bearers," were an elite corps selected for their strength, skill, and courage [10]. Armed as traditional hoplites, they could engage in the brutal push of shields and hold the line where the phalanx could not.

Philip also built a powerful heavy cavalry wing, with the most famous unit being the Companion Cavalry. Recruited from the Macedonian aristocracy and equipped with a long lance and full body armor, the Companions were shock troops par excellence [11]. In battle, they would smash into the enemy line while the phalanx pinned them from the front, a tactic Philip used to devastating effect.

Siege Engines and Engineering

Another area where Philip innovated was in siege warfare. He was one of the first generals to make use of torsion catapults, which used twisted skeins of sinew to power their shots [12]. These engines could launch heavy darts or stones with tremendous force, battering city walls and mowing down enemy ranks.

Philip also invested heavily in his army‘s engineering capabilities. His sappers became adept at constructing roads, bridges, and fortified camps, greatly enhancing his army‘s mobility and resilience [13]. He also developed a highly efficient logistical system to keep his army supplied on campaign.

Conquest of Greece

With his army rebuilt along these revolutionary lines, Philip embarked on one of the most extraordinary military careers in ancient history. He first subdued Macedonia‘s traditional enemies – the Illyrians, Paionians, and Thracians – securing his kingdom‘s borders for the first time in generations.

He then turned his attention to the fractious city-states of southern Greece. In a series of brilliant campaigns, Philip systematically defeated the most powerful states, demonstrating the supremacy of the Macedonian war machine [14]. Even Athens and Sparta, the two traditional superpowers of the Greek world, were brought to heel.

The final showdown came at the Battle of Chaeronea in 338 BC. Philip led the Macedonian right wing, while his 18-year-old son Alexander commanded the left. The Macedonian phalanx smashed through the Athenian and Theban line, while Alexander led a crushing cavalry charge that broke the Sacred Band of Thebes [15]. The slaughter was terrible, and when the dust settled, Philip stood as the undisputed master of Greece.


Philip‘s military innovations reached their apogee under his son Alexander the Great, who wielded the army his father had forged to carve out one of the largest empires the world had ever seen. And long after Alexander‘s death, armies across the Hellenistic world continued to employ the Macedonian phalanx as their core heavy infantry [16].

But it was Philip who laid the groundwork for Macedonia‘s military supremacy. By synthesizing the most cutting-edge technologies and tactics of his day into a cohesive combined-arms system, he created an army that was virtually unbeatable on the battlefield. Few military reformers have had such a profound and enduring impact.

In the words of the historian Diodorus Siculus, "Philip‘s greatest achievement was the power of his arms, and his most outstanding characteristic was his exceptional grasp of military tactics and strategy" [17]. Through his revolutionary reforms, Philip transformed warfare, and in so doing, changed the course of history.


  1. Thucydides, History of the Peloponnesian War, 4.126.3
  2. M. B. Hatzopoulos, Macedonian Institutions Under the Kings, 1996, p. 165
  3. Plutarch, Life of Pelopidas, 18.1
  4. N. G. L. Hammond, The Macedonian State, 1989, p. 104
  5. Polybius, Histories, 18.29.1
  6. Sekunda, N. (2009), The Macedonian Army, p. 23
  7. Arrian, Tactics, 12.1
  8. Diodorus Siculus, Library of History, 16.3
  9. P. Krentz, "The Nature of Hoplite Battle," CA 4 (1985) 50-61
  10. Arrian, Anabasis of Alexander, 2.23.2
  11. Sekunda, 2009, p. 42
  12. E.W. Marsden, Greek and Roman Artillery: Technical Treatises, 1971
  13. Diodorus, 16.8.7
  14. I. Worthington, Philip II of Macedonia, 2008
  15. Plutarch, Life of Alexander, 9.2
  16. D. Lonsdale, Alexander the Great: Lessons in Strategy, 2007, pp. 20-38
  17. Diodorus, 16.1.6