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The Macedonian formation terrified opponents— and at times overwhelmed the vaunted Roman legion.

ONE DAY in late June 168 Rome and Macedon were encamped be- tween Mount Olympus and the port city BC, the armies of of Pydna in Macedonia. The two empires had been at war for three years, but campaigning of late had been largely inconclusive. The Macedonian king, Perseus, son of Philip V, led a force of 40,000 infantry and another 4,000 cavalry. Rome had recently dispatched a new commander for its 35,000 troops, the consul Lucius Aemilius Paullus, an experienced soldier who had set about retraining an army that had grown lax and undisciplined.

Before Aemilius left Rome, according to Cicero, a family dog named Perseus had died, which the general took as a good omen. But when the battle at Pydna erupted, Aemilius was shaken.

The Macedonians assailed his legions with discipline and spirit, maintaining a tight formation of interlocked shields while their long pikes scattered units and shattered bodies. Aemilius later said that watching the steel bristle of the Macedonian phalanx bearing down in full charge was the most terrifying moment of his life.

The Macedonian phalanx and the Roman legion are perhaps the most famous tactical formations in antiquity. The phalanxes of Alexander the Great humbled the armies of the mighty Persian Empire, while Roman legions conquered Italy, Carthage, and Gaul. Commentators and modern military historians who compare the two formations typically conclude that the legion was far superior, particularly given several lopsided battlefield casualty counts and the ultimate victory of the Romans over the Macedonians. Yet legions won many of the clashes only by the narrowest of margins, the fighting decided by factors that had little to do with the phalanx. As Aemilius discovered that day at Pydna, the Romans often had to claw their way to victory.

The Macedonian phalanx became the premier tactical formation of the Hellenistic world after Philip II came to the Macedonian throne in 359 BC. Philip set about reforming Macedon’s infantry, in part to counter the dominance in the army of a cavalry force of independent-minded aristocrats. He recruited poor peasants who, because they could not afford the expensive panoply typical of the relatively wealthy Greek hoplites, were outfitted in a different kit.

Linen corselets (linothorax) replaced metal cuirasses. The costly and unwieldy hoplite shield, roughly three feet in diameter, gave way to a concave target just two feet across and lacking a bulky bronze rim. Hung from the neck to cover the left shoulder, this shield freed both hands to wield a 14- to 20-foot pike topped with a short iron head shaped like a leaf. Called a sarissa, it replaced the traditional eight-foot Greek hoplite spear and became the most important innovation of Philip’s reform.

He trained his infantry to move in tightly grouped formations, the front rows of men with their sarissai lowered and those further back with their pikes raised to deflect arrows. Unlike the hoplite spear, which was primarily used to stab downward in the crunch of close combat, the sarissa was thrust forward underhanded.

When thousands of soldiers with sarissai were massed tightly, the effect was a wall of pikes that was frightening and quite effective. Philip II and his son Alexander III deployed the Macedonian phalanx with such success that other Greeks imitated it. The Spartan king Cleomenes III and the Achaean general Philopoemen both issued their troops sarissai and Macedonian-style shields in the 220s BC.

The legion’s development, meanwhile, was influenced by various Italian tribes. The Romans borrowed chain mail and the Montefortino helmet—distinguished by its conical shape and round knob on top—from the Gallic tribes in northern Italy. They likely adopted javelins (pila) and oblong, concave shields from the Samnites, a central Italian people.

The shield (scutum) offered protection from the shins to the sternum. Though it did not interlock like the round hoplite shields (clipei) deployed by the earliest Roman armies, its full-body protection allowed the Romans to adopt open-order formations where men clustered around a standard but were largely free to engage in individual combat. In the mid-third century, the Romans adopted a Spanish style of sword, the gladius Hispaniensis, which had a waisted blade of between 22 and 29 inches and was good for stabbing and hacking.

A standard legion consisted of 4,200 infantry, although some deployed as many as 6,200 soldiers in major campaigns. Each was paired with a wing (ala) of Italian allies using similar equipment and tactics.

The legion was divided into 120-man units called maniples, which enhanced maneuverability in rough terrain. By the early third century, the legion fought in three lines (tres, or triplex, acies), with the maniples in checkerboard formation. The first line consisted of spearmen (hastati), soldiers in their early 20s and armed with pila. Behind them were “prime men” (principes), fighters in their mid-20s, also armed with pila. In the rear stood “third rankers” (triarii) wielding pikes. These men were veterans of the army, in their late 20s and early 30s. In the worst-case scenario, the battle might “come to the triarii” (ad triarios redisse), which formed the legion’s tactical reserve. Teenage skirmishers called “swift ones” (velites) ranged freely in front of the battle line, conspicuously seeking individual combats and youthful glory. Cavalry guarded the legion’s flanks.

The initial encounters between legion and phalanx offer mixed evidence about which tactical formation was superior. These battles came between 280 and 275 BC, when Rome was consolidating control of central Italy, and the Greek colonies in southern Italy sought help. Pyrrhus, king of Epirus, invaded southern Italy and began the Pyrrhic Wars.

The Romans lost the first two major battles, at Heraclea and Asculum. Though factors beyond infantry tactics contributed to Roman defeat at Heraclea—in particular Pyrrhus’s war elephants and Roman deficiencies in cavalry—the 40,000 Epirots and Italians at Asculum trounced an equal number of Romans in a head-to-head fight. Still, the Romans inflicted significant damage; Pyrrhus suffered nearly 4,000 dead at Heraclea and another 3,500 at Asculum.

After a four-year campaign against Carthage in Sicily, Pyrrhus returned to Italy. The legion won its first engagement against the Epirots at Beneventum in 275 BC, in part because Pyrrhus’s elephants panicked and disrupted his phalanx. Afterward Pyrrhus quit the battlefield and retreated to Greece. The Romans’ extensive manpower reserves had allowed them to recover from repeated defeats and eventually exhaust the Macedonians. Nonetheless, the phalanx had fared well—so well that most would conclude that in the Pyrrhic Wars, it had been superior to the legion.

The next major contest of phalanx and legion came 80 years later in the Second Macedonian War (201–197 BC), when Roman armies invaded Greece. Early Roman setbacks—notably the repulse of a legionary assault force from the besieged town of Atrax—led the consul Titus Flamininus to doubt the quality of his soldiers and their equipment. The decisive battle, fought at Cynoscephalae in southeast Thessaly in 197 BC, pitted an army of approximately 25,500 Macedonians under King Philip V—including a heavy phalanx of 16,000—against a consular army of 26,000.

Both sides stumbled upon each other while maneuvering in hilly terrain. Philip seized the initiative with a hasty attack, sending the phalanx on a downhill charge. The Roman left was driven back by the assault of Philip’s right wing. The Macedonian left, however, lost its shape due to rough terrain, command and control failures, and the deployment of Roman elephants. This created bifurcated combats, with the Roman right carving its way forward several hundred yards to the front of its beleaguered left.

The decisive moment of the battle came when a military tribune collected some 20 maniples from the right wing and led them to relieve the left, assailing the vulnerable rear of Philip’s forward element. Once inside the phalanx, the Romans, armed with short swords, slaughtered some 8,000 Macedonians. Philip, until then the dominant power in Greece, was forced to withdraw to his homeland and give up his fleet.

The modular form of the legion proved critical here, giving the Romans mobility over rough terrain that the phalanx did not have. But this advantage should not be overstated. The military tribune had to detach 20 disparate maniples, somehow ordering 20 head centurions to simultaneously attack in a different direction. Indeed, the commanding tribune of any legion had to control 30 maniples without any intermediate chain of command. (The cohort, consisting of three maniples, would not become a standard feature of the Roman legion until the time of Julius Caesar, roughly 140 years later.)

That the Romans turned the tide was miraculous: In the din of battle, other elements of the Roman forward line could have mistaken the maniples peeling off to counterattack as a general retreat. That could have sparked panic, and the Macedonians could have easily won.

In 191 the Seleucid Empire, which stretched from Turkey to Afghanistan and BC, ROME went to war with was ruled by Antiochus III, a descendant of Alexander’s lieutenant Seleucus Nicator. Antiochus tried to fill the vacuum in Greece after Philip V withdrew, sending an army to Thrace. After the Romans crushed Seleucid incursions in Greece, a Roman army commanded by Lucius Scipio and his brother, Publius Scipio Africanus, invaded Asia Minor (modern Turkey). Antiochus raised a 72,000-man army and engaged Scipio’s 28,000-man expeditionary force at Magnesia ad Sipylum.

The lopsided numbers did not work to the Seleucid king’s advantage. The checkerboard of Roman maniples was like an accordion. The legion could expand or contract by simply opening or closing gaps between the maniples; or it could increase or shrink the distance between the ranks. The Romans typically maintained two-foot intervals between soldiers to allow room for swordplay, with each soldier occupying a front of about six feet. The front of a 5,000-man legion could cover as much as 850 yards, or contract to less than 400 yards.

Antiochus deployed two phalanxes— one with 16,000 regulars and a second that probably numbered 10,000 elite “Silver Shield” infantry. His remaining forces consisted of some 12,000 cavalry and 34,000 light infantry. Antiochus stacked the phalanx 32 men deep—twice the normal depth. Indeed, most of the Seleucid soldiers stood in the middle of mass formations, unable to engage or even see the enemy.

The front rank of the main phalanx consisted of 500 men, while the Silver Shield brigade probably stretched just over 312 men across. Each man occupied the three-foot width of his body, standing shoulder to shoulder in close formation, which meant Antiochus’s 26,000 heavy infantry covered a mere 812 yards—a shorter front than a single Roman legion of 5,000 might present.

Antiochus had to face the rest of the Roman battle line with either cavalry or light infantry. His light infantry was no match for the legionaries, while he wasted much of his excellent heavy cavalry fixing, rather than flanking, the Roman infantry line.

Antiochus began the battle with a charge by his heavily armored cavalry (cataphracti), assisted by the vaunted Silver Shield troops. The legion and Italian ala on the Roman left were pressed back, retreating as far as their camp. The king, chasing down Roman fugitives, must have thought he was close to victory.

On the Seleucid left, the main phalanx locked in a bitter stalemate with a legion. Cavalry, not infantry, ultimately decided the battle. The Seleucid cavalry on the phalanx’s left flank collapsed in the face of an aggressive charge by Roman and allied horse. Half-surrounded, the stalwart phalanx fought on, its pikes projecting from all four sides as it endured a hail of javelins.

Wayward Seleucid elephants, maddened by Roman darts, suddenly ran amok across the weary phalanx, shattering its unified front. Roman swords flooded in amidst the swirl of discombobulated phalangites, inflicting devastating losses as the phalanx disintegrated. With nearly half his force killed, wounded, or captured, Antiochus surrendered Asia Minor to Rome.

Ancient sources provide only glimpses of frontline combat. The imaginative “face of battle” technique, a deductive approach to military history pioneered by John Keegan, offers additional insights to distill the ground-level mechanics. This method reconstructs historical battles based upon knowledge of weapons, equipment, human physiology and psychology, and battlefield conditions.

Any clash of phalanx and legion would have begun with harassment by Roman velites, who would have sniped at the phalanx with their darts and javelins. The rear ranks holding sarissai would have deflected some of these missiles, but any soldier felled would have been trampled by his own comrades as the phalanx closed ranks.

As the phalanx made its charge, the velites would fall back, withdrawing through the gaps between the maniples. How the Romans closed these gaps (or if they even felt the need to) is one of the great mysteries of ancient military history. They may have controlled the gaps with a lethal crossfire of missiles, making it virtual suicide for any enemy to venture in. In any event, the gaps would not have been a grave liability. The phalanx could not flood into those spaces without losing its cohesion.

Cohesion was key to the effectiveness of the phalanx. Sarissai drawn together into a dense forest made a phalanx virtually invincible, whether attacking or defending. The shoulder-to-shoulder formation must have given Macedonians great psychological comfort while facing down an attack. And their steamroller assaults struck tremendous fear in the enemy, often overwhelming the legion members and driving them back. This happened to significant legionary elements even in victories such as Cynoscephalae and Magnesia.

The legion’s open order, meanwhile, made it vulnerable to such attacks. To try to slow the charge of the phalanx, the hastati in the front ranks would have hurled their pila. Each man carried two, and soldiers in the rear ranks would have likely passed theirs forward to resupply their comrades. Phalangites in the front must have cowered at the sight of hundreds of iron barbs raining down upon them. But as the phalanx plowed forward, there was little the legion could do besides fall back. Holding ground was an invitation to be skewered.

The Romans were fortunate that a phalanx could not charge forever. At some point its soldiers had to slow or stop. As they grew exhausted, they risked losing the cohesion that was so critical to their success. This was the moment that the legion would have seized to counterattack. Close-quarters combat would follow, a fight that played to the legion’s strengths. It seamlessly integrated skirmishers into the matrix of heavy infantry, while its three lines provided for built-in relief and reinforcement, easily deployed through the legion’s checkerboard array. The reserve force, the triarii, was particularly important, especially when Hellenistic generals consistently failed to maintain adequate reserves.

Roman soldiers were also better equipped for close combat than the Macedonians. The sarissa was designed to break up formations and impale the enemy. But if the phalanx could be flanked or disrupted, the weapon lost much of its value. The phalangites’ round shields were small, and their training did not emphasize swordplay or individual combat. Lengthy sarissai hindered sudden maneuvers and made it difficult to react to an attack to the flank or rear.

The Roman historian Livy records the horror of Macedonian soldiers who saw what Roman swordsmanship could do: “When they viewed the mutilated bodies, with arms slashed off from the shoulder, heads hacked clean off from the body, exposed guts and other disgusting wounds, the ranks shuddered as they realized that they must stand against such weapons.”

The Roman advantage in sword- play helps explain the particularly heavy losses inflicted when they pursued defeated Hellenistic armies. Roman soldiers were no more violent or brutal than their opponents. In fact, the Greek historian Polybius believed that the Macedonians possessed the most warlike personalities, “delighting in war as if it were a feast.” The Roman soldier simply had the tools and training to inflict heavier losses when the matter came down to individual combat.

The strengths and weaknesses of both the phalanx and the legion were on display at Pydna, the last encounter of the Roman legion and the Macedonian phalanx. Opening skirmishing—possibly sparked by fighting over a runaway mule—soon developed into a full battle. Perseus committed his 21,000-strong phalanx as Roman ranks struggled to form. The shock value of the phalanx was readily apparent. The Romans were driven back by its charge, and early attempts to counterattack failed. A desperate Italian centurion even threw his maniple’s standard into the impenetrable array of pikes, motivating a doomed berserker charge by allied troopers, who attempted in vain to retrieve their colors.

Had the Romans panicked while falling back under this pressure, the initial charge could have won the day for the Macedonians. Yet the phalanx began to fall apart in the pursuit, especially as it maneuvered over a rough patch of ground. Aemilius Paullus ordered his maniples to flow into gaps as they opened, relying on the initiative of centurions and common soldiers to seize opportunity where they saw it. The phalanx, once compromised, never recovered. When the Macedonians took flight, the battle devolved into an orgy of butchery, with 20,000 Macedonians killed and 11,000 taken prisoner.

The Battle of Pydna established Roman supremacy throughout the Eastern Mediterranean. Perseus surrendered shortly afterward, and Rome abolished the Macedonian monarchy.

Aemilius Paullus returned to Rome in 167 and celebrated the triumph, displaying the captive king. Yet the victorious general in private often recalled the fury of the phalanx and his own initial sense of despair when standing in its path. He clearly knew how easily the battle might have gone the other way.


Originally published in the Winter 2011 issue of Military History Quarterly. To subscribe, click here.