Sparta had always been classed as the strongest and most feared city-state in Greece. This was to change following the battle of Leuctra in 371BC.
Sparta wanted the Boeotian Confederacy to be abolished but the city-state of Thebes refused and battle was to ensue on the plain outside the village of Leuctra.
The Spartans had expected Thebes to refuse and had already positioned their forces near to the village of Leuctra in Boeotia.
There is speculation as to the size of the armies, but it is believed that the Spartan army and their allies consisted of 10,000 hoplites and 1,000 cavalry, and the Boeotian/Theban force of around 6 – 7,000 soldiers, 1,500 cavalry and skirmishers.
The Spartans were to attack Theban camp followers as they were retreating back to Thebes and they were forced back towards the Theban army.
The Spartan leader Cleombrotus positioned his hoplites in the traditional phalanx formation, with his most experienced soldiers on the right side, the place of honour.
Epaminondas, the Boeotian leader decided to try something more radical that hadn’t been seen before. He placed his cavalry and light infantry in front of his fifty deep phalanx formation directly opposing the Spartan right then placed his best soldiers, the Thebans in the left side to directly oppose the elite Spartan warriors. The centre and right of the formation he left much shallower.
The Theban left were hand picked soldiers (the sacred band of Thebes) led by Pelopidas (Theban statesman and general).
The conventional way of battle was to make the right wing the strongest, but Epaminondas ignored this.
A cavalry engagement took place in which the Boeotian army triumphed.
The full battle then ensued.
Epaminondas sent his formation forward against the Spartan right. The Spartan line, around twelve deep, had no power to stop the impact of their opponent’s line.
Around 1,000 Spartans were killed, many of these were their most experienced warriors. Their leader Cleombrotus also died at this time.
Seeing that the more experienced right wing of their formation was destroyed, many of the Spartan allies that had not originally been keen to fight, now retreated and left the field.
The Theban elite had destroyed Sparta at battle. Thebes now became the most powerful city-state in Ancient Greece.