The Spartans are generally regarded as the one of the greatest warrior societies in history. The soldiers who made up the Spartan ranks were perhaps the toughest ever, with grueling military training that started at childhood. However while toughness is an advantage, it is often unreliable unless tempered with smarts and intelligence. Take Navy Seals, for example, generally regarded as among the most badass soldiers today. Many don’t know that they are also among the most intelligent soldiers. They have to learn an incredible number of things, like math, science, navigation, medicine, electronics, technology, parachuting, diving, combat tactics, etc. etc. etc., and often learn it in a short amount of time. The same is true with most other elite special forces in other military branches and other countries. Back during peashooter’s teaching days, he once had a student who was a strapping young lad, very athletic and very tough, who wanted to be a Navy Seal. Physically he had a chance of achieving his goals, but he never applied himself academically. Mr. Peashooter had to break it to him that if he didn’t have high grades, score high in standardize testing, and most importantly score high in the ASVAB (military testing), it would be highly unlikely he would even be considered for training.
After the Peloponnesian War Sparta came to dominate Greece. Many in Greek city states hailed the Spartans as liberators, seeing the former Athenian rulers as corrupt tyrants. However, Greece soon learned that the new boss was no better than the old boss, as the Spartans soon brought Greece in line with an iron fist. One Greek city state called Thebes was so resentful of Spartan rule that it revolted against Sparta in 387 BC, thus declaring itself independent and instituting a new democratic government. A six year long war ensued, and amazingly the Thebans were able to hold the line against the Spartans by conducting brilliant raids, surprise attacks, and through the construction of large fortifications (Spartans were not good at siege warfare).
By 371 BC the Theban Army was manned by a group of tough and experienced soldiers. More importantly, they were led by the brilliant Theban general named Epaminondas, a man who was an expert at solving problems by thinking outside of the box. On that same year, the Spartans organized a grand army of Spartan soldiers and other Greek Allies with the intent of ending the rebellion once and for all. The army number around 10,000 with another 1,000 cavalry. In contrast, the Theban Army only numbered around 6,000 - 8,000. It was obvious to Epaminodas that victory could not be achieved through brute force alone. Thus, he came up with a grand idea that would bring the mighty Spartan Empire to its knees.
In ancient Greek warfare, phalanxes met opposite of each other in straight lines, with roughly equal columns and ranks (if possible). It was a traditional honor that the best soldiers were placed on the right wing, thus the veterans had the privilege of slaughtering the less experienced. Epaminodas’ goal wasn’t to satisfy honor, he was in it to win. Instead of placing his best to the right, he placed them on the left flank so that his best would face their best. He then placed more units on his left, so that in all the left flank was fifty ranks deep, and also placed all his cavalry on the left. Traditionally, Greek armies engaged all at once, smashing into each other until once side was victories or defeated. Epaminodas’ attack with his army staggered in echelon formation, thus making his left the spearhead of the attack. While such tactics were new and revolutionary at the time, they would become a staple of future warfare, with generals such as Alexander the Great, Frederick the Great, and Napoleon Bonaparte using similar formations to win epic battles.
When the battle commenced, the Theban left flank, comprising of 50 rank deep column, smashed against the opposing Spartan right flank, which was only 8-12 ranks deep. Overpowered by the massive assault, the Spartans immediately lost 1,000 of their best soldiers, as well as their king, Cleombrotus I. The other Greek allies, most of whom were slaves or unwilling participants, turned tail and ran at the sight of the mighty Spartans being butchered, and their right flank being turned. Those Spartans and Greeks who stood their ground were surrounded and massacred.
The Battle of Leuctra was the first time the Spartans were defeated in an open battlefield. Once news spread across Greece that the Spartans had been defeated the city states rose up in revolt. More importantly, the helots, Spartan slaves who were the backbone of the Spartan economy, likewise rose up and rebelled against Sparta. In the end, Sparta was forced to sue for peace, and would lose its status as a major power in Greece as the city state enter a brutal and sad decline. As decades proceeded Greek and Macedonian leaders such as Philip II, Alexander the Great, and King Pyhrrus would develop even smarter and better tactics. In the meantime, Spartan warfare would never change, and thus Spartan ways become quaint and dated. By the time of the Punic Wars, Spartan technology and tactics were laughable at best. Spartan independence ended in 192 BC when it was annexed by the Aechaen League, and in 146 BC when it was conquered by Rome.