Phalanx: ancient Greek expression to signify an organized, dense line of battle; the heavily armed infantry soldiers were known as hoplites.
Although representations of soldiers in densely packed battle lines date back to the third millennium BCE in the ancient Near East, the word phalanx is usually used to describe Greek armies. The first Greek author to use the word φαλαγξ is Homer, and in his poems it means something like an organized battle line. This is remarkable because in Homer's poems, warriors fight individual combats whereas the soldiers in a phalanx (the hoplites) fight as a group. However, it is reasonably clear that Homer's duels were in his age already becoming anachronistic.
Initially, tactics must have been very simple. The heavily-armed soldiers, recruited from the upper class of a town (because only they could afford arms and panoply), were standing in long, parallel lines, close to each other. Every hoplite carried a large round shield (the aspis or hoplon) which covered his own left side and the right side of the man to his left. A phalanx was, therefore, very densely packed and could not easily turn to the left or right. If its allowed to compare war with sport: a hoplite battle was something like a "scrum" in a rugby match: both sides, armed with spears, tried to push over the enemy, and once a phalanx was victorious, the losses at the other side were extremely heavy, because the victors would use their swords to kill the defeated men.
Standing in a battle line and waiting for the clash with the enemy took considerable courage, as the playwright Euripides suggests in a diatribe against the demigod Heracles, who was...
... a man who has won a reputation for valor in his contests with beasts, in all else a weakling; who ne'er buckled shield to arm nor faced the spear, but with a bow, that coward's weapon, was ever ready to run away. Archery is no test of manly bravery; no! he is a man who keeps his post in the ranks and steadily faces the swift wound the spear may plough.
Wounds were likely, and therefore, the hoplites were protected by a breastplate, greaves, their hoplon, and a tunic of stiffened linen. Their offensive weapons were, as already noted, a spear and a sword - the latter only to be used in the second phase of the battle. The soldiers must have been strong men, because the full panoply could weigh as much as 15 kg, and it comes as no surprise that foreigners often noted that the Greek soldiers were "men of bronze" or "men clad in iron".note[Herodotus, Histories 2.152; Ptolemy III Chronicle.] On the reliefs on the eastern stairs of the Apadana in Persepolis, it is not the Yaunâ (Greeks) but the Carians who are armed like hoplites, but it was generally admitted that the latter had developed part of the hoplite panoply.
The original tactic, which we compared to the rugby scrum, was essentially a one-dimensional way to fight a battle. The development of hoplite warfare made it increasingly two-dimensional. The famous battle of Marathon (490 BCE) is one of the first recorded instances in which the phalanx was employed in a more creative way. The Persians seriously outnumbered the Athenians, and the Greek commander Miltiades was forced to stretch his lines, to prevent outflanking. At the same time he strengthened his wings, even when this meant that the center was weakened.
During the battle, the Athenian wings destroyed the Persian wings, and turned against the center. If we are to believe the body count after the battle, the Athenians lost 192 men in the ensuing mêlée, their opponents 6,400. This is exaggerated (6,400 = 192 × 331/3), but no doubt the invaders suffered severely.
The obvious response to an attack by a phalanx was a first strike by light armed spearmen and archers. Their missiles would break the ranks of the attacking phalanx. At the same time, cavalry could be placed on the wings, which could attack the enemy's rear once the battle had started.
In the diagram to the right, the smaller (red) army has a fair chance against the larger (pink) army.
During the Peloponnesian War, which lasted from 431 to 404 and was fought all over the Greek world, warfare became increasingly professionalized. At Mantinea in 418 (more...), we see the first instance of a realignment of the troops after the battle had started, something that had never been attempted before.
The main innovation, however, was the oblique phalanx. The first experiments took place during the Corinthian War (395-387), but it was during the Battle of Leuctra in 371 that its devastating potential became clear. The Theban commander Epaminondas placed his troops at an angle with the Spartan troops and fortified one of his wings. in this way, he was able to concentrate his forces on one section of the Spartan battle line. The Thebans broke through the Spartan lines, and their victory was complete.
King Philip II of Macedonia, who had spent his youth as a hostage in Thebes and knew Epaminondas personally, further improved the phalanx. Until then, it had been eight to sixteen lines deep, but now, twenty lines were more common. The spear, which had been two to three meters long, was now replaced by a lance (sarissa) with a length of about six meters. Because a hoplite now needed both hands to carry his weapon, his shield was made smaller.
Once the battle had started, the battalions of hoplites -or, as they were now called, pezhetairoi, "foot companions"- forced the enemy to stay at the same place ("to hold 'em by the nose"), while the cavalry attempted to break though the lines of the enemy and tried to reach their rear ("kick 'em in their balls").
Battle had by now become a very flexible affair. At Chaeronea (338), the main cavalry units were on the left wing and the phalanx advanced obliquely; at Issus (333), the phalanx was a straight line and the main cavalry unit, commanded by Philip's son Alexander the Great, was on the right wing.
Alexander's conquest of the Punjab and the valley of the Indus meant the introduction of the war elephant, which was used against enemy cavalry, which could never keep its line of battle when faced by these monsters. (The soldiers in the phalanxes usually had special sarissas that were used to attack the trunks, whereas archers could attack their eyes.) At the same time, units became more varied: heavy cavalry was used to force a break into the enemy's lines, light troops were used to protect or disturb the phalanx, and sometimes, even catapults could be employed.
As a result, the phalanx was one of several units that could be employed by a general. However, it was still the most important instrument to force the enemy to stay at the same place and it was still the most important part of the army once the battle had been won and the enemy had to be killed.
The main weakness of the phalanx alway was that its right wing was poorly protected, because hoplites had their shields on their left arm. (The historian Thucydides describes how phalanxes always drift a bit to the right.) Another important weakness was that the phalanx could only operate on a plain; hills would break the line of battle, and an enemy would enter these openings. Finally, if the battle lasted very long, the first line of men would collapse of sheer exhaustion.
The first encounter between a Greek phalanx and a Roman legion was the battle of Heraclea in 280, in which Pyrrhus of Epirus overcame his Italian enemies, but suffered heavy losses because the Roman army was more flexible and could replace the soldiers in the first line; they could continue to fight much longer. This flexibility was Rome's main advantage, especially when rearrangements had to be made during the battle - something that was always necessary during a fight on a hilly terrain. In June 197, at Cynoscephalae, the Roman commander Titus Quinctus Flamininus overcame the Macedonian king Philip V, and the Greek historian Polybius of Megalopolis concluded that this battle was the best example to show that legions were superior to the phalanx.note[Polybius, World History 18.28-31.]