A millennium-and-a-half before Frederick the Great, Epaminondas of Thebes changes the face of warfare with the oblique attack and forever destroyed the myth of Spartan invincibility !
The Peloponnesian War indisputably established Sparta as the paramount power in the Greek World. Though that long conflict had been waged, ostensibly, by Sparta to free the Greek city-states of the Delian League from Athenian dominance; the Spartan victory merely replaced Athenian hegemony with Spartan.
Though superb soldiers, the Spartans were educationally and temperamentally ill-equipped to deal with the subtleties of statecraft and diplomacy necessary for managing an empire. Over the next 33 years following the end of the Peloponnesian War, Sparta faced sporadic challenges from the other leading Greek states; with coalitions forming against her and her interests. Of these, the Thebans were both the most implacable and the most dangerous.
Thebes had been an ally of Sparta against Athens; and had even pushed for the total destruction of that city after its surrender in 404 BC. However, the following year Thebes aided in the restoration of the Athenian democracy; rightfully perceiving a revived Athens as a counter-balance to Spartan power. Over the next two decades, she often found herself at odds with Sparta; culminating in defeat in the Corinthian War, after which her Boeotian League (through which Thebes exercised leadership over the other Boeotian cities) was dissolved. The crowning agony came in 382 BC, when a Spartan force treacherously seized and occupied the city; establishing once again a oligarchical government.
Theban hoplites (drawing by James Carrozza*)
Three years later, the pro-Spartan government was overthrown by a coup, led by the dashing young Theban firebrand, Pelopidas and his friend, the philosopher-soldier, Epaminondas. A virulently anti-Spartan democracy was installed; and for the next eight years a desultory war was waged to drive the Spartan garrisons out of Boeotia and reestablish the Theban-dominated Boeotian League.
During this period Epaminondas and Pelopidas alternated command; training and improving the Theban forces. Pelopidas was particularly successful at leading small-unit operations; and in his hands the 300 strong Theban corps-de-elite, the Sacred Band became a formidable and professional body of soldiers, fully capable of facing the vaunted Spartan hoplites in battle. Skirmishing with the Spartans year-after-year, the Thebans both learned the Spartan’s method of making war; and lost their awe of Spartan military prowess.
This small cadre had started its existence as the citadel guard of the city; all chosen for their valor. Uniquely in Greek history, the entire corps was composed of homosexual couples; each man paired side-by-side with his lover. It was felt that lovers would fight like lions to protect their beloved; and under Pelopidas’ leadership the Sacred Band were indeed a corps of lions.
Boeotian hoplites. Boeotians fetishized the naked male form to a higher degree than perhaps any other Greeks; and partial nudity may not have been uncommon, even in battle. Note the boots worn by the central figure: while most Greek warriors fought barefoot, the Boeotians often wore boots. The back figure (in red) is a Theban. Note the “club of Heracles” device, the symbol of Thebes on his shield. This might have been the shield device used by Theban hoplites; while the lion head might have been used, alternatively, by the members of the 300-strong elite corps, the Sacred Band.
In 371 B.C. the hitherto invincible Spartan army once again invaded Boeotia, this time with the purpose of finishing Thebes for good.
The Boeotians had little time to muster their full soldier levy. In consequence, they were outnumbered by the Spartan invaders when the two sides met on the plain of LEUCTRA, in southern Boeotia. The Spartan army numbered some 10,000 hoplites, at the core of which were 700 elite Spartiates, the true Spartan citizen-soldiers; and 1,000 cavalry. The Boeotians numbered approximately 6,000-7,000 hoplites, perhaps 1500 cavalry, and a similar number of skirmishers. Of these number, no more than 4,000 were Thebans.
Neither side was initially eager for battle. The Spartan King, Cleombrotus, was convinced by his senior officers that he must fight or be indicted by the ephors when he returned to Sparta. The Boeotians were even more nervous about facing the Spartans. But the Thebans knew that if this army didn’t fight now, their Boeotian allies would return home to defend their own cities; and the Spartans would isolate and besiege Thebes. For several days the Boeotarchs  debated offering battle to the superior Spartan forces. But Epaminondas, who argued for giving battle, won the day.
The intellectual Epaminondas, a military innovator of the first-order, had devised a plan to defeat the vaunted Spartans (who had not lost a pitched-battle in three centuries). Though most of his Thebans were not as well trained as the Spartans, they were mainly comprised of “big country boys”; farmers who were both strong and large. Boeotia means “cow land”; comprised of broad pasture land, where cattle grazed. Likely the Thebans had a larger amount of beef in their diet; which would also account for a larger, heavier man. By contrast, the Spartans tended to be smaller and wirier of build, due to the spare, near-starvation diet they were raised on in the Spartan Agoge . Epaminondas knew from experience that in a pure shoving contest his larger and stronger Thebans were a match for the Spartans.
One of the hallmarks of Greek hoplite warfare was a tactic called othismos, the push of shields. Though the precise explanation of this tactic is debated by scholars, I believe it involved each hoplite in the phalanx pressing his shield into the back of the man in the rank in front of him; and using the weight of the entire phalanx to press the enemy phalanx backward. Once falling backward, a phalanx quickly lost cohesion as men tripped over each other, and rout soon followed. The Spartans were masters of othismos, advancing in ordered ranks with measured tread, every man keeping time to the trill of the flutes; steadily and silently bearing down upon the enemy.
Few Greeks would stand up to the feared Spartans. At Mantinea of 418 BC the Arcadian and Athenian phalanx broke and fled from the Spartans before making contact:
(they) “did not even stand to fight, but they fled as the Spartans approached; some were even trampled in their hurry to get away before the enemy (Spartans) reached them.” 
However, Epaminondas knew that his Thebans would meet the Spartans, and in the push of shields his larger, stronger Thebans would have an inherent advantage. And with the fiery Pelopidas leading the Sacred Band, spearheading the Theban attack, he was confident he had men equal to the Spartans in valor and skill at arms.
Unlike the Spartans, who advanced at a measured walk, the Thebans had trained and practiced advancing rapidly, and as they neared the enemy to break into a dead run, aiming to shatter the enemy formation rather than merely pushing them back.
Epaminondas had one more trick to play, and this one would be revolutionary.
First, knowing that in Greek hoplite battles each side always placed their best troops on the far right of their battle line; he deviated from the norm and placed his best troops, the Thebans, on his left flank, opposite the Spartans themselves. The rest of his forces, comprised of the allied non-Theban Boeotians, were to be back to the right. By this he was gambling that his Thebans would defeat the unbeatable Spartans; and keep his less reliable Boeotian allies out of the battle till a decision could be reached.
Never before had a phalanx deployed in echelon formation; nor had the best troops been placed on the left end of the line.
To give even great pushing power of his Theban hoplites, he arrayed his Thebans in an uncommonly deep formation.
Greek phalanxes deployed in an average depth of 8-12 ranks. In fact, as few as four ranks were not unusual. The Spartans, masters of phalanx warfare, deployed their own phalanx that day 12 ranks deep, as Epaminondas expected. The Thebans, at least since the Peloponnesian War, had experimented with phalanxes twice as deep as the norm; making up with mass what they tended to lack in training.
At Leuctra, Epaminondas arrayed his Thebans in an unprecedented, massive column almost as deep as it was broad: a human battering ram 50-men deep (or, as the Greeks would term it, “shields” deep); with Pelopidas and the Sacred Band at its head. Their orders were to charge foremost, leading the rest of the Theban phalanx; and to aim directly for the Spartan king, Cleombrotus, where he would have taken his station: on the rightmost of the Spartan line, surrounded by his bodyguard of Spartan knights, the “hippeis”.
Thus, Epaminondas’ plan was to strike the strongest point of the Spartan army, where their king, his bodyguard, and the Spartiates would be stationed. If these were defeated, and quickly, he reasoned the rest of the Spartan army, comprised of allies who looked to Sparta to lead the way, would lose heart. In essence he planned to cut off the head of the snake, and let the rest of the body die on its own.
The battle began with the skirmishers and cavalry dueling between the two hosts. In this initial phase, the Theban cavalry got the better of the fight. Then, as the two opposing phalanxes approached each other, these got out-of-the-way for the main event: the push of shields.
As the Theban column bore down on them across the shallow valley, the Spartans were unconcerned. They had fought the Thebans many times before, and knew their proclivity to charge in column. The counter to which, as with any column attack, was to extend ones own line and envelop the column once it had become bogged down in the shoving contest. Cleombrotus gave the order for his Spartans to extend their line, the rear 6 ranks of the phalanx attempted to spread out to their right, sacrificing depth for frontage.
What the Spartan king didn’t foresee was the dash and élan with which Pelopidas and the Sacred Band would close the distance between them.
Coming on at breakneck pace, the Theban spearhead struck the Spartans while still in the midst of this change of formation. The Spartans were caught unprepared, moving; rather than braced for the collision of two phalanxes.
Pelopidas and the Sacred Band smashed into the Spartan hippeis at the very point where Cleombrotus and his command staff were standing, directing the realignment. Disaster for the Spartans quickly followed, as the king and the hippeis were at first born backwards like flotsam on the tide; then overthrown and trampled into the dust. Cleombrotus was mortally wounded and ushered off the field, his men desperately covering his retreat.
Lending their weight to the Sacred Band’s assault was the massive Theban column; a shimmering tide of brazen shields and helmets, and glittering iron spearheads. They pushed into the chaos created by the Sacred Band’s assault, further ripping apart and trampling the thin red Spartan line. The Spartans held for a short time, fighting stubbornly as they were born backward.
In minutes, the history of Greece was forever changed, and the myth of Spartan invincibility overturned. As their king and his officers fell, the Spartan ranks shattered and then broke.
As Epaminondas had hoped, his Boeotian allies never had to strike a blow: When they saw the Spartans break, the Peloponnesian allies withdrew back to the Spartan camp, without striking a blow.
The Thebans made no effort to pursue them. As was customary in Greek warfare, they instead erected a trophy of stacked enemy shields and spears taken from the fallen; and sent a herald to the Spartan camp, granting permission to come and collect their dead and wounded. This customary permission by the victor to the vanquished was formal recognition by both parties of who held the field. For the Spartans, long accustomed to granting and not receiving such permission, this must have been a bitter pill to swallow, indeed!
The Spartans lost 1,000 men. Of these, 400 hundred were elite Spartiates, who died where they stood. At that time in its history, the manpower of Sparta had been in sharp decline for over a century. The total manpower of Sparta at this time was only some 1,200 true Spartiates. Thus, at Leuctra a third of the military manpower of Sparta died along with their king.
Though the Spartan would attempt once again to best Epaminondas and his Thebans at Mantinea in 362, it would prove a repetition of Leuctra; with Epaminondas gaining a second victory, though losing his life in the process.
In its day, Leuctra was the “shot heard round the world”; a signal moment in which the balance of power shifted forever from Sparta and the Peloponnese. First to Thebes, which would establish in the decade after a brief hegemony; then, a generation later, to Macedon. Young Philip of Macedon was a hostage in Thebes in the years immediately after Leuctra; and was able to study the methods of Epaminondas and Pelopidas first-hand.
Greek warfare would never be the same. No longer would a two phalanxes of citizen hoplites dominate the battlefield; with a simple push of shields deciding the issue. Commanders were finding new ways to utilize their heavy troops, new methods of piercing an enemy line. Combined-arms forces of cavalry and light infantry, augmenting the heavy infantry of the Greek battle line, would replace the hoplite armies of old.
Epaminondas had not just revolutionized Greek warfare, he had given future tacticians a new trick to add to their playbook: the echeloned (sometimes called an “oblique”) advance. This tactic would allow armies to gain a local superiority at one, decisive point on the battlefield; while withholding their most unreliable troops from combat till a decision was reached. It would be used by the great Macedonians, Philip and Alexander to effect; Frederick the Great of Prussia would win immortal fame at the Battle of Leuthen in 1757 using just such an approach.
The Leuctra monument at the battle site. Note the representations of Spartan shields along the top.
Here is a very well done documentary by History Channel:
 The chief officers of the Boeotian Confederacy
 The “Rearing”, the training program all Spartan boys underwent from age 8 till manhood. The boys were given little to eat; and were encouraged to “forage” from the countryside.
 Thucydides, The History of the Peloponnesian War 5:63
* Visit James Carrozza’s website here!
FOR FURTHER READING:
And this one: