Why Didn`t Leonidas & His Spartans Retreat? The Truth!

The Battle of Thermopylae in 480 BC is not only one of the most famous battles in all of history but also one of the 4 major battles in the Greco-Persian Wars. But whenever the Battle of Thermopylae is brought up, then one question soon follows: Why didn`t Leonidas and his Spartans retreat? Why did they stay behind and fight to the death? Well, that will be answered in this article.

Leonidas as the supreme commander and the Spartiates as the most reliable troops were responsible for blocking the passage of Thermopylae until the Greek navy had passed through a closeby narrow passage into safety. Leonidas probably hoped to retreat as soon as that was achieved but was surprised by the speed of the Persian advance. He fell when he led a Spartan counterattack with the purpose of buying time for his own retreat.

Let`s take a closer look. But before we can look at why Leonidas and the Spartans continued to fight at Thermopylae we first have to look at why the Greeks decided to fight there in the first place.

The Greek goal in the Battle of Thermopylae

I actually wrote an entire article where I talk in depth about why the Greeks decided to fight at Thermopylae and why that battlefield was the only reasonable choice.

The goal of the Greek army that fought at Thermopylae was not to defeat the Persian army – the Greek army was way too small for that. The goal was to buy time and give the Greek fleet enough time to find an opportunity to defeat the Persian fleet. Since the Persian army and the Persian fleet relied on each other, the loss of the fleet would have forced the Persian army to retreat even without being beaten on the battlefield.

Do you want to find out more about the size and composition of the Greek army at the Battle of Thermopylae? Then I would like to recommend you my article here.

And here you can find out more about how the Persian army and the Persian navy relied on each other and why the defeat of the navy would have forced the Persian army to retreat.

So the entire plan at the battle of Thermopylae was to buy time for the Greek fleet so that the fleet could find a good opportunity to inflict a crushing defeat on the Persian fleet. And, at least in theory, the chances were pretty good for that since the Greek fleet – while still numerically inferior to the Persian fleet – was still quite strong and the Persian fleet had already suffered significant losses in a storm.

There was just one problem: The Greek fleet could not defeat the Persian fleet despite fighting for 3 days. This battle, the naval Battle of Artemisium, started on 19 August 480 BC and occurred simultaneously with the Battle of Thermopylae.

And while on the third day of the two battles, the naval battle was still not decided, the situation of the land-based forces under the command of Leonidas worsened. A detachment of Persian elite soldiers managed to bypass the passage of Thermopylae, which was still blocked by the troops of the Hellenic League with the help of a native guide.

Suddenly the situation became desperate since an encirclement of the Greek army became imminent. And when the passage of Thermopylae came under Persian control, then a nearby fairway that was only 49 ft / 15 m wide but had to be used by every retreating ship of the Greek navy would have also fallen under Persian control. Since that fairway was so narrow that it could easily be blocked, that would have meant that the Greek fleet would be trapped and the war would be lost.

Or in other words:

The passage of Thermopylae had to be held until the last Greek ship had made it through the narrow fairway into safety. Only when the remains of the already reduced Greek fleet could escape south there was still hope to win the war. The loss of the fleet would have meant the end of the war and the Persian victory.

And that brings us to Leonidas and why Leonidas and his Spartans continued fighting even though encirclement by the Persians was imminent.

Why did Leonidas stay and fight in the Battle of Thermopylae?

As mentioned, the passage of Thermopylae needed to remain in Greek hands until the last Greek ship had made it south through the narrow fairway close to the passage of Thermopylae.

Why Leonidas Had to Stay Behind!

Leonidas knew that only if enough Greek ships escaped, victory over the Persians was still possible.

The problem was that while Leonidas was willing to defend the passage as long as necessary/possible, other commanders saw that differently.

Let me explain: Yes, Leonidas was one of the two Spartan kings and he was the supreme commander of the army that fought at Thermopylae. But that army didn`t only consist of Spartans. Only 300 Spartans fought in the Battle of Thermopylae, the rest of the 7,000 men strong army was made up of contingents from other city-states of the Hellenic League!

And many of the commanders of the contingents of other Greek city-states were not willing to stay and fight but wanted to retreat instead. Leonidas simply didn`t have the authority to force these men to stay since they came from independent city-states and were not under Spartan control!

And indeed, the survivors of the Greek army except for Leonidas, 300 Spartans, 700 Thespians, 400 Thebans and an unknown number of Helots (who had been forced to accompany the Spartans) left the passage of Thermopylae. Of those who stayed behind, only the Thebans survived since they surrendered fast enough.

The ancient Greek writer Herodotus (one of our prime sources for the Persian Wars) claims that 4,000 of the 7,000 men, who fought at the Battle of Thermopylae, died. That number sounds pretty high and was certainly much higher than the typical casualty rate of a Hoplite battle. But Herodotus and the numbers he claims always have to be taken with a grain of salt, more on that here. Speaking of Herodotus, I can highly recommend his book, „The Histories“*, in which he describes the Persian Wars if you want to experience the Persian Wars through the eyes of an ancient Greek.

But let`s now finally answer the question of why Leonidas and his Spartans didn`t retreat at the Battle of Thermopylae.

As mentioned, the passage of Thermopylae needed to be held until the last Greek ships had escaped south. It was the responsibility of Leonidas as the supreme commander to ensure that the passage was held long enough for that. And since the 300 Spartans were not only under the direct command of Leonidas, but also the most reliable troops (although they probably didn`t have the level of professionality that later generations of Spartan warriors would have), they would also stay behind to enable the retreat of the Greek fleet through the narrow fairway.

Now, Leonidas did most likely not plan to sacrifice himself in the Battle of Thermopylae! The idea that Spartans were prohibited from retreating is actually a myth that I debunk in my article here.

Leonidas & His Plan to Buy Time and Retreat Later

So, what was the plan of Leonidas after the bulk of his army had left?

It seems most likely that Leonidas wanted to slow down the Persian advance for some time and then also retreat with the rest of his forces. That is also supported by the place of his death. Leonidas fell at the northern gate of the passage of Thermopylae (that was north of the original defensive positions). That meant that right before the death of Leonidas the remaining Greeks had advanced from their defensive positions against the Persians.

So the plan of Leonidas was most likely to counterattack and disturb the Persian units while they were still getting into formation. That would have bought enough time to allow the Greek fleet to escape. And the chaos in the Persian ranks would have given Leonidas and his men a chance to retreat right before the Persian encirclement closed around them.

But that never happened since Leonidas was hit and killed by a Persian arrow while leading the counterattack against the Persian lines that were still getting into formation for their final assault on the Greek lines. After the death of Leonidas, the remaining Greek soldiers (except for the Thebans) continued to fight since any hopes of retreat had died with Leonidas.

So it shows that Leonidas had most likely never planned to sacrifice himself and his men at Thermopylae. Indeed, the Battle of Thermopylae was a military and political catastrophe for Sparta since not only one of the two kings, but also 300 of the few full citizens of Sparta had died.

It was only after the Persian Wars (which were eventually won by the Hellenic League) that the deaths of Leonidas and his men were idolized as a willing sacrifice. That idolization can still be seen today, for example with the sentence: return on your shield or with your shield. (Here you can find my article where I debunk that sentence and the myth around it).

Ok, so now we know why Leonidas didn`t retreat from the passage of Thermopylae: He had planned to but died while trying to buy time for the retreat.

But there are still a couple of other unanswered questions:

Why did the Greeks only deploy a small army to the Battle of Thermopylae?

One other commonly asked question is why the Greek army at the Thermopylae was so small. And indeed, 7000 men is not a lot compared to other ancient Greek armies.

Historians don`t know why the Greek army at the Battle of Thermopylae was so small and why Leonidas didn`t call for reinforcements.

However, there are several possible explanations. But they are little more than speculation. The entire defense plan of the Hellenic League was pretty improvised, so it is possible that that caused the relatively low army size at Thermopylae. It is also possible that the confidence in the plan of fighting at Thermopylae was pretty low.

Now I hate to end this article on that note, but Historians simply don`t know why the army at the Thermopylae was so small and why Leonidas didn`t call for reinforcements.

But I hope that you enjoyed this article despite the unsatisfactory answer to the last question.

Coming back to the Persian Wars, the Battle of Thermopylae was not pointless. The Greek fleet was able to (mostly) retreat because the Greek army held the passage of Thermopylae long enough. The same fleet would be able to crush the Persian fleet in the Battle of Salamis. And in the Battle of Plataea the biggest Hoplite army in history, which was once again led by Sparta, was able to defeat the Persian army.

The naval Battle of Salamis (mostly a victory of the Athenian fleet) and the Battle of Plataea (mostly a win of the Spartan army) were two of the 4 major battles of the Persian Wars and ended the Persian Wars.

But these victories would also fuel the rivalry between Athens and Sparta since both claimed that they were mostly responsible for the victory over the Persians. That rivalry should eventually lead to the Peloponnesian War, a war that lasted 27 years and that is sometimes called an ancient world war.

But that is a story for another time.

Take care of yourself because you deserve it. You really do.

Until next time

Yours truly

Luke Reitzer


Herodotus: The Histories.*

Karl-Wilhelm Welweit: Sparta. Aufstieg und Niedergang einer antiken Großmacht (Stuttgart 2004).

Plutarch: On Sparta.*

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