So we introduced the notion of a phalanx, which combines the spear hedge with the shield wall.
But what tactics do we have with phalanx?
The basic structure of the phalanx was to take part in a huge line, with the most experienced soldiers on the right.
Then the two armies smash into each other.
The first formation is an oblong square of a large front, of common use both in ancient and modern times, although not thought the best by various judges of the service, because an even and level plain of an extent sufficient to contain its front cannot always be found, and if there should be any irregularity or hollow in the line, it is often pierced in that part. Besides, an enemy superior in number may surround either your right or left wing, the consequence of which will be dangerous, unless you have a reserve ready to advance and sustain his attack. A general should make use of this disposition only when his forces are better and more numerous than the enemy's, it being thereby in his power to attack both the flanks and surround them on every side.De Re Militare
The battle line's weakness is flanking! That becomes the "name of the game" for tacticians. Flanking could be done with light infantry or cavalry.
This actually leads us to ask: is there any other method of flanking? Yes, indeed there is: if one sets up in a different formation, it becomes trivial. Lets consider that formation.
Vegetius was the first to thoroughly study the oblique formation in De Re Militare, Book III §19 "Various Formations for Battle".
Alexander the Great made this formation famous, and with it he conquered the (then) known world.
But the first instance of this echelon/oblique formation dates back to the Boetian war, specifically the Battle of Leuctra.
Case Study: Battle of Leuctra
The Battle of Leuctra (fought July 6, 371 BC) between the Thebans and Spartans. The main sources for this battle are Xenophon's Hellenica, Book 6 Chapter 4; and Diodorus Siculus' Bibliother Historica, Book XV §§53–56. (Although Plutarch's "Pelopidas," §§20–23 mentions it as well!)
JFC Fuller gives us the short version of events:
Had it not been for the Theban commander, Epaminondas, there can be little doubt that Thebes would have succumbed. But he realized that the Spartans would never change their traditional shock tactics, the success of which depended on an advanced in perfect order, all spears of the phalanx striking the enemy's front simultaneously, and devised a tactic which would prevent this and throw the phalanx into confusion. Instead of drawing his troops up into parallel lines to the Spartan army, he formed them into oblique order to it[sic], with his left leading and his right drawn back. At the same time he massed on his left wing a column of troops fifty ranks deep. Its object was to meet shock by supershock and simultaneously to have enough reserve force in hand to lap around the enemy's right wing. In July, 371 BC, he met King Cleombrotus and the Spartan army at Leuctra (near Domvrena) in southern Boeotia, and by means of these tactics decisively defeated him, Cleombrotus being killed. This battle not only broke the charm of Spartan prestige, but brought the short-lived Spartan hegemony to its end.(Military History of the Western World, vol. 1, pg. 83)
If you dislike reading, you can watch the YouTube video:
Take the narration with a grain of salt, as few records exist indicating the cavalry re-entered the fight or charged the flank of the Spartan battle line.
Xenophon suggests that Spartan heavy infantry got involved in the Theban cavalry when the Spartan cavalry fled (broken in a sideshow engagement with Theban cavalry).
Xenophon's exact phrasing is: "Cleombrotus had hardly begun to lead his division against the foe when, before in fact the troops with him were aware of his advance, the cavalry had already come into collision, and that of the Lacedaemonians was speedily worsted. In their flight they became involved with their own heavy infantry; and to make matters worse, the Theban regiments were already attacking vigorously."
However, Diodorus suggests otherwise: "There being no one in command of the wing, the heavy column led by Epameinondas bore down upon the Lacedaemonians, and at first by sheer force caused the line of the enemy to buckle somewhat; then, however, the Lacedaemonians, fighting gallantly about their king, got possession of his body, but were not strong enough to achieve victory. For as the corps of élite outdid them in feats of courage, and the valour and exhortations of Epameinondas contributed greatly to its prowess, the Lacedaemonians were with great difficulty forced back; at first, as they gave ground they would not break their formation, but finally, as many fell and the commander who would have rallied them had died, the army turned and fled in utter rout."
(And as best I am aware, it was Philip and Alexander the Great who started using cavalry to hammer away at the enemy's line! I suspect if Epameinondas used cavalry in this manner, accidentally or otherwise, the strategy would have been copied quickly and Philip would have had a harder time uniting Greece...)
The battle line is drawn thus (according to the Department of History, United States Military Academy; a dubious source! :p):
Note that the Thebans advanced heavily on the Spartan's right flank and routed it. Lets reiterate: the Thebans routed the most elite portion of Sparta's battle line.
We can understand how the rest of Sparta's battle line chose retiring from battle, rather than fighting it.
The next feature of the combat was that in consequence of the flat space of plain between the opposing armies, the Lacedaemonians posted their cavalry in front of their squares of infantry, and the Thebans followed suit. Only there was this difference--the Theban cavalry was in a high state of training and efficiency, owing to their war with the Orchomenians and again their war with Thespiae, whilst the cavalry of the Lacedaemonians was at its worst at this period. The horses were reared and kept by the wealthiest members of the state; but whenever the ban was called out, an appointed trooper appeared who took the horse with any sort of arms which might be presented to him, and set off on the expedition at a moment's notice. Moreover, these troopers were the least able-bodied of the men: raw recruits set simply astride their horses, and devoid of soldierly ambition. Such was the cavalry of either antagonist.
The heavy infantry of the Lacedaemonians, it is said, advanced by sections three files abreast, allowing a total depth to the whole line of not more than twelve. The Thebans were formed in close order of not less than fifty shields deep, calculating that victory gained over the king's division of the army implied the easy conquest of the rest.
Cleombrotus had hardly begun to lead his division against the foe when, before in fact the troops with him were aware of his advance, the cavalry had already come into collision, and that of the Lacedaemonians was speedily worsted. In their flight they became involved with their own heavy infantry; and to make matters worse, the Theban regiments were already attacking vigorously. Still strong evidence exists for supposing that Cleombrotus and his division were, in the first instance, victorious in the battle, if we consider the fact that they could never have picked him up and brought him back alive unless his vanguard had been masters of the situation for the moment.
When, however, Deinon the polemarch and Sphodrias, a member of the king's council, with his son Cleonymus, had fallen, then it was that the cavalry and the polemarch's adjutants, as they are called, with the rest, under pressure of the mass against them, began retreating; and the left wing of the Lacedaemonians, seeing the right borne down in this way, also swerved. Still, in spite of the numbers slain, and broken as they were, as soon as they had crossed the trench which protected their camp in front, they grounded arms on the spot whence they had rushed to battle. This camp, it must be borne in mind, did not lie at all on the level, but was pitched on a somewhat steep incline. At this juncture there were some of the Lacedaemonians who, looking upon such a disaster as intolerable, maintained that they ought to prevent the enemy from erecting a trophy, and try to recover the dead not under a flag of truce but by another battle. The polemarchs, however, seeing that nearly a thousand men of the total Lacedaemonian troops were slain; seeing also that of the seven hundred Spartans themselves who were on the field something like four hundred lay dead; aware, further, of the despondency which reigned among the allies, and the general disinclination on their parts to fight longer (a frame of mind not far removed in some instances from positive satisfaction at what had taken place)--under the circumstances, I say, the polemarchs called a council of the ablest representatives of the shattered army and deliberated as to what should be done. Finally the unanimous opinion was to pick up the dead under a flag of truce, and they sent a herald to treat for terms. The Thebans after that set up a trophy and gave back the bodies under a truce.Hellenica VI §10–15
Diodorus writes (regarding the battle):
54. An aider and abettor of this device was Leandrias the Spartan, who had been exiled from Lacedaemonian and was then a member of the Theban expedition. He was produced in the assembly and declared that there was an ancient saying amongst the Spartans, that they would lose the supremacy when they should be defeated at Leuctra at the hands of the Thebans. Certain local oracle-mongers likewise came up to Epameinondas, saying that the Lacedaemonians were destined to meet with a great disaster by the tomb of the daughters of Leuctrus and Scedasus for the following reasons. Leuctrus was the person for whom this plain was named. His daughters and those of a certain Scedasus as well, being maidens, were violated by some Lacedaemonian ambassadors. The outraged girls, unable to endure their misfortune, called down curses on the country that had sent forth their ravishers and took their lives by their own hands. Many other such occurrences were reported, and when Epameinondas had convened an assembly and exhorted the soldiers by the appropriate pleas to meet the issue, they all shifted their resolutions, rid themselves of their superstition, and with courage in their hearts stood ready for the battle. There came also at this time to aid the Thebans an allied contingent from Thessaly, fifteen hundred infantry, and five hundred horsemen, commanded by Jason. He persuaded both the Boeotians and the Lacedaemonians to make an armistice and so to guard against the caprices of Fortune. When the truce came into effect, Cleombrotus set out with his army from Boeotia, and there came to meet him another large army of Lacedaemonians and their allies under the command of Archidamus, son of Agesilaüs. For the Spartans, seeing the preparedness of the Boeotians, and taking measures to meet their boldness and recklessness in battle, had dispatched the second army to overcome by the superior number of their combatants the daring of the enemy. Once these armies had united, the Lacedaemonians thought it cowardly to fear the valour of the Boeotians. So they disregarded the truce and with high spirits returned to Leuctra. The Boeotians too were ready for the battle and both sides marshalled their forces.
55. Now on the Lacedaemonian side the descendants of Heracles were stationed as commanders of the wings, namely Cleombrotus the king and Archidamus, son of the King Agesilaüs, while on the Boeotian side Epameinondas, by employing an unusual disposition of his own, was enabled through his own strategy to achieve his famous victory. He selected from the entire army the bravest men and stationed them on one wing, intending to give to the finish with them himself. The weakest he placed on the other wing and instructed them to avoid battle and withdraw gradually during the enemy's attack. So then, by arranging his phalanx in oblique formation, he planned to decide the issue of the battle by means of the wing in which were the élite. When the trumpets on both sides sounded the charge and the armies simultaneously with the first onset raised the battle-cry, the Lacedaemonians attacked both wings with their phalanx in crescent formation, while the Boeotians retreated on one wing, but on the other engaged the enemy in double-quick time. As they met in hand-to‑hand combat, at first both fought ardently and the battle was evenly poised; shortly, however, as Epameinondas' men began to derive advantage from their valour and the denseness of their lines, many Peloponnesians began to fall. For they were unable to endure the weight of the courageous fighting of the élite corps; of those who had resisted some fell and others were wounded, taking all the blows in front. Now as long as King Cleombrotus of the Lacedaemonians was alive and had with him many comrades-in‑arms who were quite ready to die in his defence, it was uncertain which way the scales of victory inclined; but when, though he shrank from no danger, he proved unable to bear down his opponents, and perished in an heroic resistance after sustaining many wounds, then, as masses of men thronged about his body, there was piled up a great mound of corpses.
56. There being no one in command of the wing, the heavy column led by Epameinondas bore down upon the Lacedaemonians, and at first by sheer force caused the line of the enemy to buckle somewhat; then, however, the Lacedaemonians, fighting gallantly about their king, got possession of his body, but were not strong enough to achieve victory. For as the corps of élite outdid them in feats of courage, and the valour and exhortations of Epameinondas contributed greatly to its prowess, the Lacedaemonians were with great difficulty forced back; at first, as they gave ground they would not break their formation, but finally, as many fell and the commander who would have rallied them had died, the army turned and fled in utter rout. Epameinondas' corps pursued the fugitives, slew many who opposed them, and won for themselves a most glorious victory. For since they had met the bravest of the Greeks and with a small force had miraculously overcome many times their number, they won a great reputation for valour. The highest praises were accorded the general Epameinondas, who chiefly by his own courage and by his shrewdness as a commander had defeated in battle the invincible leaders of Greece. More than four thousand Lacedaemonians fell in the battle but only about three hundred Boeotians. Following the battle they made a truce to allow for taking up the bodies of the dead and the departure of the Lacedaemonians to the Peloponnese.Bibliother Historica, Book XV
Lets note that the Spartans held their own. Xenophon remarked the Spartans' held their own despite that their situation
speedily worsted, whereas Diodorus said otherwise:
As they met in hand-to‑hand combat, at first both fought ardently and the battle was evenly poised; shortly, however, as Epameinondas' men began to derive advantage from their valour and the denseness of their lines, many Peloponnesians began to fall. For they were unable to endure the weight of the courageous fighting of the élite corps; of those who had resisted some fell and others were wounded, taking all the blows in front. Now as long as King Cleombrotus of the Lacedaemonians was alive and had with him many comrades-in‑arms who were quite ready to die in his defence, it was uncertain which way the scales of victory inclined; but when, though he shrank from no danger, he proved unable to bear down his opponents, and perished in an heroic resistance after sustaining many wounds, then, as masses of men thronged about his body, there was piled up a great mound of corpses.
What could have helped the Thebans win this battle faster?
First, the Theban cavalry could have been wheeled around and run down the routing units. This development actually is refined by Alexander the Great into the "Hammer and Anvil" tactic (we discuss this elsewhere).
Note that in this approach, using the cavalry to attack the rear, requires the cavalry being heavy cavalry...although light cavalry could work for a short engagement. If it gets prolonged, the cavalry gets endangered.
Second, being 50 ranks deep but only the first 4 ranks or so could engage the enemy...puts one at a disadvantage.
Wouldn't it be better if more ranks could engage the enemy?
How do we accomplish this? With a longer spear! This leads us to Alexander the Great and Macedonian "phalangites".
Homework: what could the Spartans have done to defeat the Thebans?
Homework: could the Spartans have possibly (re)deployed according to the Theban allocation of manpower?
(NB: we may eventually post some possible solutions to these homework problems, and discuss their merits.)