And perhaps even more significant, as demonstrated by this excellent piece on military history, is the importance of tactical flexibility:
Few ancient warriors have amassed such an enduring and widely known legacy as the Spartans. From the cinematic reimagining, to the science fiction super soldiers of the Halo series, to the use of the word Spartan itself as a synonym for arduous and ascetic ruggedness – Spartans are, for many, the archetypical warrior. Most with at least a cursory knowledge of ancient history know the Spartans by acclaim to be the best warriors of all the Greeks.
It is true that the Spartans fielded notably competent and powerful armies. This, of course, had less to do with some sort of genetic predisposition for combat, and more to do with the structure of Spartan society. In the classical era, most Greek city-states fielded citizen armies – quite literally the adult male population under arms, with farmers and craftsman mobilizing into a militia. In contrast, Spartan society was decidedly more martial, even in peacetime. Sparta had a large workforce of slaves (helots) who comprised the majority of the population – Herodotus claimed that there were something like seven helots for each Spartan. The presence of such a large, servile labor force enabled Spartan men to participate in rigorous military-social institutions, including regular training in arms and a military academy for young men. So while the average Athenian soldier was likely to be a farmer who grabbed the family shield, spear, and helmet when he was called up, a Spartan was more like a professional soldier who had helots to do the farming for him.
Sparta’s peculiar social structure and martial institutions bore their intended fruit. From roughly 431 to 404 BC, the Spartans fought a protracted conflict with Athens (the Peloponnesian War) which shattered Athenian preeminence in southern Greece and established Sparta as the dominant Greek power. This struggle witnessed many decisive Spartan victories, including the famous Battle of Syracuse, which saw an Athenian army entirely crushed by Sparta and her proxies.
The Battle of Leuctra brought a sudden, unexpected, and spectacular end to the era of Spartan hegemony.
Athens and Sparta are by far the two best known ancient Greek city states – Athens for its philosophers and Sparta for its warriors. Far less famous is Thebes – the third city of Greece. Yet it was this same uncelebrated Thebes that won a decisive victory against the Spartans, despite being heavily outnumbered, crushing the Spartan army and breaking its power….
At Leuctra, the Spartans arrayed in standard formation, with their battle lines formed up at 8 to 12 ranks deep. This was viewed as the correct formation to ensure both adequate depth and width. In short, the considered “best practice” was to maintain a properly balanced formation, with as little drift or dissipation as possible, to prevent the formation from breaking apart altogether. A broken formation was deadly. It is estimated that, in Greek hoplite battles, losing armies lost on average nearly three times as many men as winning armies. This was the price of a shattered phalanx.
At Leuctra, Epaminondas and the Thebans threw all the conventional wisdom out the window.
Instead of a balanced, rectangular formation, the Thebans assembled in a lopsided, weighted formation, with their left wing packed, both with far deeper ranks and their best troops. While the Spartans followed the conventional wisdom and lined up at a consistent depth all across the line, the Thebans assembled a massive package, fifty ranks deep, on the left (facing the Spartan right).
By forming up the vast bulk of their forces in the left wing (in a formation 4 to 5 times deeper than a traditional Hoplite mass), the Thebans had already deviated from one standard practice of the time. They abandoned a second standard operating procedure when they proceeded to advance that left wing far ahead of the remainder of their line. While the 50-deep left-hand mass smashed into the Spartan right, the Theban center and right lagged far behind. As a result, the mass of the overweight Theban left broke through the Spartan right wing and began to roll up the rear before the rest of the Spartan line even engaged in battle. Most of the Spartan army never got to join the battle before their formation was shattered from the rear. The Theban mass rolled into the rear, began concentric attacks on the Spartan army, and sparked a total rout in short order.
Leuctra was a titanic victory with massive geopolitical implications. The loss of an army to an outnumbered and underestimated foe rocked both Sparta’s material strength and its perception as the leading military power in Greece, and set in motion a strategic defeat that permanently relegated it to a second rate power within Greece.
The Battle of Leuctra also marked the beginning of the end of classical Greek hoplite warfare, with its focus on uniform, tactically simplified heavy infantry formations. To a modern reader, the strategy adopted by the Thebans at Leuctra, aimed at a decisive action to penetrate and exploit the enemy line, seems fairly obvious. Yet to accomplish this, the Thebans had to break a variety of “rules” for hoplite warfare, massing their forces into what the Spartans surely viewed as an unwieldy, imbalanced, and excessively deep left wing. Innovation rarely looks like innovation to those that have the benefit of hindsight, but the Thebans had, in a word, discovered the power of schwerpunkt. Thebes would itself soon be overwhelmed by another Greek power fielding similarly flexible, but even more powerful phalanx formations: Macedonia.
Epaminondas’ tactics at Leuctra marked one of the earliest documented examples of coordinated and planned battlefield maneuver.The History of Battle: Maneuver, Part 1, 4 November 2022
Keep the Battle of Leuctra in mind whenever you’re tempted to “stick to the plan” in the face of a situation that has obviously departed from what was anticipated. If the Spartans had simply withdrawn in order to figure out the probable consequences of the anomaly they were witnessing at Leuctra, they might have been able to adapt to it and overcome it, thereby changing Greek history and preventing Sparta’s decline.
Mindless sticking to one’s pre-established position, either physically and conceptually, can be fatal.