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What was the Battle of Thermopylae? A 5 minute guide

Updated: Jun 20, 2023

This August marked the 2500th anniversary of the Battle of Thermopylae. But what was this battle, and why do we remember it over two and a half millennia since it was fought? You, the person reading this, are probably a very busy student/parent/teacher (delete as applicable) with limited time for wading through long-winded articles on Greek military history. So let's see if I tell you all you need to know about the Battle of Thermopylae in only five minutes!

The Return of the Empire

Chuck them down the well - Courtesy M. A. Barth

Back in 491 BC the dominant world power was the Persian Empire. Historians state that the size of the empire was, and I quote, “freakin’ massive!” Its King, Darius the Great, ruled millions of subjects and had a vast army that crushed all that stood before it into a mushy pulp. This made it rather odd that, having sent Persian Heralds to the teeny tiny city states of Ancient Greece, the Greeks responded by tossing said heralds down a pit and a deep dark well.

This was clearly bonkers behaviour, why anger the might of the Persian Empire? The only reason is that the Greeks did not want to accept Persian Authority.

A carving of Xerxes courtesy Darafsh

It was eleven years later, in 480 BC that Darius’ son, the hard to pronounce King Xerxes, decided to finally put the Greeks in their place. He amassed a humongous army and ginormous fleet and set off to crush Athens and Sparta. However, before Xerxes left on his jolly jaunt of death and wanton violence, he sent a messenger to one of the two Kings of Sparta; King Leonidas.

The messenger demanded that the Spartans surrender their arms. Don’t worry, he wasn’t requesting that they chop off their arms from their own bodies and present them to Xerxes - that would have been very gruesome (not to mention difficult to do, how do you chop off that second arm having chopped off the first? And who would want that many bloody arms anyway?). The messenger actually meant that they should surrender their weapons. Leonidas responded with one of the most awesome one-liners in all of history, “Come and take them!” The Persians decided to do just that.

The Road to Battle

Courtesy Cleber.knfire

The Persian Army headed south, quickly conquering Northern Greece on its way. The Greek Army, led by Leonidas, had only one chance, to hold the Persians back in the narrow straits of the pass of Thermopylae. They figured that fighting in the narrow pass would mean the Persian Army couldn’t surround them as there just wasn’t enough space. The Greeks only had 7000 Hoplites, whereas the Persians had 70,000 to 300,000 soldiers – quite the difference! Why didn’t the Greeks have a larger army you say? That’s because most of them had chosen to go and compete in the Ancient Olympics and take part in holy festivals instead.

Let’s get Ready to Rumble!

Ellis, Edward Sylvester, 1840-1916; Horne, Charles F. (Charles Francis), 1870-1942

The narrow pass worked perfectly to the Greeks advantage, preventing the Persians from putting the full might of their army in the field. For two days the Greeks held the pass, fighting ferociously. The Spartans apparently said all sorts of cool things during this time. Herodotus – an ancient Greek historian – writes that on learning there would be enough Persian arrows shot at them to “block out the sun”, a Spartan soldier replied, “So much the better…then we shall fight our battle in the shade.”

The Greeks were organised in a Phalanx formation, their bronze armour, shields, and deadly long spears proving impossible for Xerxes and the Persians to punch through. Xerxes sent thousands of warriors down that pass but none succeeded in routing the Greeks.

Betrayal most horrid!

Courtesy Ward

Perhaps the Greeks could have kept on holding the pass, were it not for the harsh betrayal they suffered from one of their own. Ephialtes, a citizen of Greece, told Xerxes about a secret pass that would lead the Persians around the Greek formation, allowing them to attack from the flank. Ephialtes was rewarded for his treachery with copious treasure – the rotter!

With the Greeks now surrounded, Leonidas called a war council where they decided that the majority of their army should retreat. All that is, apart from Leonidas and his bodyguard of 300 Spartans.

Oh, and 1,100 Boeotians and all the Spartan slaves stayed too.

Last Stand

The last stand of the Spartans. Courtesy M.A. Barth - 'Vorzeit und Gegenwart", Augsbourg, 1832

Why didn’t the Spartans retreat? That would go against their code of honour. Spartans are trained from childhood to be soldiers and were only allowed to return from battles with their shields in hand or laid upon them. So basically, return victorious or die trying. They weren’t going to win this battle, so death rather than surrender was the next best thing.

The Spartans fought bravely against the unimaginable numbers of the Persian Army but were soon wiped out.

Every single one of them, including King Leonidas, was killed. The Persian victory allowed Xerxes to continue conquering for a bit longer.

The End?

Why then is the Spartan stand at Thermopylae fondly remembered? Normally, the battles that get written down in the history books are glorious victories, not painful defeats, right? Well, the deeds of those Greeks and their bravery are celebrated because of their heroic sacrifice and because they stood against unbeatable odds.

They also slowed the Persians down just enough to ultimately allow the remaining Greeks to be victorious and triumph in the Greco-Persian Wars, but that's a story for another day.


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