Late on a December evening in 379 BC, seven Theban political exiles, walking among a group of labourers, passed unnoticed through one of the city gates. Two nights later, in collaboration with allies inside the city, they assassinated the leaders of the oligarchic government.
By dawn, following the lead of the returned exiles, armed revolutionary activists filled the streets of Thebes. Outside the city, marching in to support the rising, was a larger group of Theban exiles, along with an expeditionary force from neighbouring Athens.

The commander of the garrison in the Theban citadel (a force of 1,500 Spartans deployed there to back the oligarchy) had been taken completely by surprise. Rather than fight, he negotiated the withdrawal of his force. The Theban Democratic Revolution of 379 BC was complete. What no-one yet realised was that this was the beginning of a wave of revolution across Greece that would destroy the power of Sparta forever.
Sparta the superpower
When Athens was filled with marble monuments and works of art, Sparta still had the appearance and feel of a large village. The city was neither architecturally sophisticated nor commercially developed. The reason was simple: Sparta was a stark society of soldiers and serfs, and the business of the state was war and internal security.
The peculiarity of Sparta had deep roots. The ruling class was descended from Dorian invaders, who had conquered Lakonia (the south-eastern quarter of the Peloponnese) in the distant Dark Age between c.950 and 750 BC. Many of the indigenous people lost their land to new Spartan overlords and were forced to work for them as serfs or helots.
Then, in two further wars during the succeeding Archaic Age (c.750-500 BC), the Spartans conquered Messenia (the south-western quarter of the Peloponnese), turning the previously independent Messenian Greek population into helots, like so many of the native Lakonians.
So the Spartans became a military elite supported by a mass of agricultural serfs. The adult male citizens who formed the Spartan Army numbered only about 2,000 in the early 4th century BC, each one supported by a state farm staffed by helots. To maintain their position, they had to hold down tens of thousands of reluctant subjects. It was for this reason that the whole of Sparta was organised as a military camp, and that every adult male Spartan was a full-time professional warrior. Everything was sacrificed to military prowess (see ‘The Spartan military training system’ on page 25).
Hoplite warfare
The result was that the Spartans had the only proper army in Classical Greece. All other city-states fielded part-time militia. Every citizen had an obligation to serve – as cavalry if they were rich enough to own horses, as heavy infantry (‘hoplites’) if they belonged to the large middling group of farmers and traders who could afford the necessary arms and armour, and otherwise as either light infantry or rowers in the war fleet. In practice, cavalry were few and of poor quality, and light infantry usually played only a minor role in land warfare. The decisive arm was the ‘phalanx’ of armoured spearmen.
Hoplites in phalanx stood shoulder-to-shoulder and ranged four, eight, even 12 ranks deep. Their large round shields overlapped along the front of the formation. A line of levelled spear-blades projected forwards above the shield-wall.

Battles were decided by the frontal collision of opposing phalanxes. As they closed, each phalanx had a tendency to veer to the right, as each man in the line attempted to tuck himself securely behind the shield of his neighbour. Consequently, at the moment of collision, one’s own right was likely to overlap the enemy’s left, making it almost certain that any successful breaking of the line would occur here. The military convention, therefore, was to place one’s main offensive weight on the right.
Tight-packed and dependent for its security on maintaining an unbroken front, the phalanx needed discipline, order, and a steady tread. In Classical Greek warfare – militia warfare – these were in short supply. Consider these words of the Greek historian Thucydides describing a hoplite battle: ‘The Argives and their allies advanced with great violence and fury, while the Spartans came on slowly and to the music of many flute-players in their ranks. This custom of theirs … is designed to make them keep in step and move forward steadily without breaking their ranks, as large armies often do when they are just about to join battle.’
The Spartan Army was small, but its unmatched professionalism made it the master of the Classical Greek battlefield. By 379 BC, Sparta had become hegemonic across Greece.
Over-extended and deeply conservative
But Spartan power was but a thin crust. Sparta’s traditional policy had been to avoid major military commitments outside her own territory. The Army’s primary role was internal security; when it fought abroad, it left the homeland open to helot revolt. Sparta’s greatest fear was of military defeat abroad being the signal for revolution at home. This, for example, was the reason that only 300 Spartans fought at Thermopylai: they were a token force designed to show solidarity with Greek allies; the bulk of the Army was retained in the Peloponnese.

But after final victory over Athens and her democratic allies in the long-running Peloponnesian War (431-404 BC), some of Sparta’s leaders had become overconfident and too eager for the glory and riches to be had in foreign adventures. Other Spartans of rank followed their lead, keen to use military victory to secure oligarchic power across Greece and thereby underwrite long-term Spartan security. Democracy was a living symbol of hope to the oppressed: for Sparta’s leaders, a ruling caste based on serfdom, its extinction was in the interests of the state.
It was this consideration that brought a Spartan military garrison into Thebes at the invitation of local oligarchs. It formed part of a wider network of client regimes and Spartan garrisons across the city-states of Greece. But, as events proved, it stretched the small Spartan military elite to breaking-point. Sparta, in the long run, was too small and impoverished to establish a lasting conservative hegemony.
Epaminondas and the Theban military revolution
Among the band of exiles who arrived at Thebes on the first morning of the revolution was a young democrat called Epaminondas. He was closely allied with Pelopidas, who had led the secret band of assassins, and these two become the dominant politico-military figures of the Theban Revolution. As well as purging the old regime and creating new democratic structures, they carried out a major reform of the Theban city-state militia – turning it, in effect, into an army capable of breaking the power of Sparta, spreading revolution across Greece, and making the city-state of Thebes hegemonic.
A central characteristic of the traditional phalanx was that force was distributed fairly evenly along the entire length of the line. The strongest phalanx might be placed on the right, but it would have the same depth and alignment as those in the centre and on the left. A second characteristic was that it operated largely independently of both cavalry and light infantry; ‘combined-arms’ operations were exceptional in Classical Greek warfare. The Spartans, in particular, were wedded to conventional hoplite battle. Their social system made them intrinsically conservative, and their long record of military success gave them little cause to question established practice.
In 379 BC, Pelopidas and Epaminondas chucked out the manual, and in the years following they remodelled the Theban Army into a combined-arms force designed to achieve concentration of force and irresistible shock-power at a chosen critical point on the battlefield. Their method – nothing less than a revolution in war – is best understood by analysis of Epaminondas’s masterpiece, the Battle of Leuktra, in 371 BC

The Spartan military training system
The Spartan agoge – its military training system – was a ruthless process of weeding out and toughening up. Weak or deformed babies were put out to die. Boys attended boarding school from six to 20 years of age, where they were subjected to a brutal regime of deliberate neglect and mistreatment. Underfed and ill-clad, they learned survival by fighting or stealing for food, but faced floggings if they got caught. Games, of course, formed the core of the curriculum: an endless round of exercises, competitions, and violent sparring, all performed naked, all under the watchful eye of a state-appointed inspector. The out-of-shape were flogged.
Grouped in age-based agelai (‘herds’) while at boarding school, young men passed directly into age-based sussitia (‘mess-groups’) when they graduated at the age of 20. For the next ten years, they spent most of their time living in military-style dormitories, feeding on the infamous Spartan ‘black broth’. Only at the age of 30 did a Spartan man come fully of age and have the right to marry, live at home, and take his place in the Assembly.
The heavy phalanx
The Spartan King Kleombrotos had succeeded in outmanoeuvring Epaminondas so as to invade the Plain of Boiotia in Central Greece (the territory of Thebes). This forced the Theban general to accept pitched battle on relatively open ground against what the ancient sources record as being a larger army.
The Spartans deployed in the usual manner, their own phalanx on the right, their allies in the centre and on the left, and the whole array of uniform depth and alignment. Epaminondas, on the other hand, deployed the Theban phalanx, the strongest part of his army, on the left – that is, facing the Spartan elite. Moreover, whereas the Spartan phalanx was formed 12 ranks deep, the Theban phalanx was no less than 50 ranks deep.
Depth of formation had a sinister but essential purpose in pre-modern warfare. When battle depended on the collision of large masses of men fighting hand-to-hand with edged weapons, it was the press of men behind, who were relatively safe, that prevented the escape of the men actually fighting in the front ranks. The men in the rear ranks could also filter forwards to replace casualties and relieve the weary – but this was secondary to their main function. This becomes obvious once the tentative character of heavy-infantry collision has been grasped.
‘Collision’ is, in fact, the wrong word; ‘confrontation’ is more accurate. Men do not hurl themselves onto bristling hedges of razor-sharp blades. The reality of heavy-infantry combat was of men stopping short, separated by a few yards of ground, and engaging in a protracted stand-off, with hurling of missiles, lunging of spear-points, dashes forwards by individuals, and occasional mass surges and pushes. The dominant emotion is fear, the main priority survival, and the basic stance defensive. What prevented a line of heavy infantry breaking the first time the enemy concerted a massed surge was the weight of men behind. The strength of the line depended on the moral and physical force exerted by the rear ranks. The 50-deep Theban phalanx was effectively unbreakable in head-on confrontation.
But would it be able to break the opposing line? Epaminondas’s second innovation was to deploy a new Theban elite in the front ranks of the ‘heavy phalanx’. This elite was the 300 men of the Sacred Band (see ‘Regiments: the Theban Sacred Band’ on page 30) – 150 pairs of male lovers fighting side-by-side. The heavy phalanx not only had massive weight; it also had a sharp cutting-edge.
Attack in echelon
The problem, of course, was that increased depth meant reduced width. What was to prevent the rest of the Theban line, shortened and weakened to make possible the deployment of a heavy phalanx on the left, from being overwhelmed? Epaminondas’s conception was to ‘refuse’ the rest of the line by deploying it in a left-to-right echelon. The heavy phalanx on the left was the forward-most element at the start of the battle. The other phalanxes were deployed like the steps of a stairway running away to the right.

The plan was for the heavy phalanx to attack the strongest part of the enemy line (his right) at the beginning of the battle, crush it, and then turn onto the flank of his centre – before the rest of his line could come to grips with those in front of them.
Additional security for the weak centre and right of the Theban Army was provided by cavalry and light infantry. The Theban cavalry in particular were more numerous and effective; they defeated the Spartan cavalry opposed to them, and then threatened the left flank of the Spartan line, discouraging it from pushing forwards to engage and envelop the weak and ‘refused’ Theban right.

The outcome
The battle unfolded according to plan. The Theban heavy phalanx smashed into the Spartan right. For a time, there was ferocious fighting between the two opposing elites, the Theban Sacred Band on one side, the Spartan king, his kinsmen, tent-companions, and royal guards on the other. But the weight of the Theban phalanx was decisive, and the collapse of the opposing formation came quickly enough to prevent the rest of the Spartan line coming into action.
When the unthinkable happened – when the Spartan phalanx broke on the right – the rest of the army retreated. Nearly a thousand were killed, of whom 400 were Spartan citizens.The ‘Spartiates’ – as the adult male Spartan citizens of fighting age were known – numbered only about 2,000 in all at this date. About a third of these, some 700, had fought at Leuktra and formed the right-wing phalanx. That 400 of them had been killed is testimony to the savagery of the struggle. This loss, which included the King and several other senior Spartans, amounted to a full fifth of Spartan military manpower.

Leuktra left Sparta physically and morally shattered. In the following years, Epaminondas embarked on a war of liberation across the Peloponnese. He encouraged the Arkadians to build a new federal capital at Megalopolis, creating a central Peloponnesian bulwark against Sparta. He freed the Messenian helots, refortified their ancient stronghold of Ithome, and left them independent and in control of the whole of the south-western Peloponnese.
He marched clean through Lakonia, the historic homeland of the Spartans, and twice attacked the unwalled city itself, being beaten back only after fierce fighting in the barricaded streets. Sparta survived, but as a second-rate power, never again in a position to challenge for control of Greece.
A political revolution had given rise to a military revolution. This had then transformed the balance of power in Classical Greece. The supreme architect of this upheaval was Epaminondas of Thebes.

But the ripples of the revolutionary years of 379 and 371 BC spread wider still. A young prince from the north spent time with the Theban generals and their army on campaign. When he returned home and became king, he remodelled his army on Theban lines and used it to conquer Greece: Philip of Macedon.
His son, Alexander, used the same army to conquer half of Asia. Central to the empire-winning method of the Macedonians was the use of the heavy phalanx, attack in echelon, an elite strike force, and combined-arms operations to achieve concentration of force at the decisive point. It was a method they had learned from the revolutionary democrat, Epaminondas of Thebes.
SUMMARY
• A heavy phalanx formed up to 50 ranks deep
• An elite strike force at the front of the phalanx
• Use of cavalry and light infantry to harass, threaten, and paralyse the enemy phalanx
• Deployment in echelon to ‘refuse’ weaker parts of the line and permit concentration of force at the decisive point
Photos: © Peter Connolly and AKG Images unless otherwise stated.