The Battle of Thermopylae, fought between the Greeks and the Persians in 480 BCE, has gone down in history as one of the most significant last stands of all time, despite the fact the “hero,” the Greeks, walked away from this battle defeated and on the brink of complete destruction.
However, when we dig a bit deeper into the story of the Battle of Thermopylae, we can see why it has become such a beloved tale from our ancient past. First, the Greeks, who have had a tremendous influence in the formation of world culture, fought this battle to protect their very existence. The Persians, who had grown over the previous century to be the most powerful empire in western Asia and the second largest empire in the world, set out to bring the Greeks under their control once and for all. To add to this, Xerxes, the Persian king, was out for revenge after the Greeks had defeated his father just 10 years prior. Lastly, the Greeks were grossly outnumbered. Xerxes prepared for his invasion by amassing one of the largest armies the ancient world had ever seen.
All of this meant the Greeks were firmly entrenched as the underdogs, but even so, they fought hard and did everything they could to beat the odds. This determination in the face of almost certain defeat is part of the reason why the Battle of Thermopylae is such a famous story. To help show this, we’re going to go over some of the key events that took place leading up to and during the battle, and also discuss how the Battle of Thermopylae impacted the overall course of Greco-Persian Wars.
The Battle of Thermopylae: Fast Facts
Before going into much more detail about the events that took place leading up to and during the Battle of Thermopylae, here are some of the most important details of this famous battle:
- The Battle of Thermopylae took place at the end of August/beginning of September in 480 BCE
- Leonidas, one of the Spartan kings at the time (Sparta always had two), led the Greeks, whereas the Persians were led by their emporer Xerxes, as well as his main general, Mardonius.
- The battle resulted in the death of Leonidas, who became a hero for his decision to remain behind and fight to the death.
- The Persian army at the beginning of the battle is estimated to have numbered 180,000 with most of the troops being taken from the various regions of the Persian empire.
- The Greek army, which was made up of Spartans, Thebans, Thespians, and soldiers from several other Greek city-states, totaled around 7,000
- The Battle of Thermopylae was one of many battles fought between the Greeks and the Persians during the Greco-Persian Wars, which took place between c. 499 BCE and c. 450 BCE.
- The Battle of Thermopylae lasted a total of seven days, but there was no fighting on the first four, as the Persians waited to see if the Greeks would surrender.
- The Greeks, despite being severely outnumbered, were able to fight back the Persians during two days of fighting.
- The Greeks were ultimately defeated when one of their own betrayed them by alerting Xerxes of a route around the Pass of Thermopylae
- Despite losing, the Greeks killed around 20,000 Persians. In contrast, the Greeks lost just 4,000 men, according to estimates made by Herodotus.
- After the Battle of Thermopylae, and using the same tactics that allowed them to inflict heavy damages on the Persians, the Greeks managed to defeat the Persians at the Battle of Salamis (naval) and the Battle of Plataea, which effectively ended the threat of Persian invasion and tipped the scales of the Greco-Persian Wars in the Greeks’ favor.
Leading Up to the Battle
The Battle of Thermopylae was just one of many battles fought between the Greeks and the Persians in a conflict known as The Greco Persian Wars. Throughout the 6th century BCE, the Persians, under Cyrus the Great, had gone from being a relatively unknown tribe hidden away on the Iranian plateau to Western Asia’s superpower. The Persian Empire stretched from what is modern-day Turkey, down to Egypt and Libya, and all the way east almost to India, making it the second largest empire in the world at the time next to China. Here’s a map of the Persian Empire in 490 BCE.
Greece, which operated more as a network of independent city-states that alternated between collaborating and fighting with one another than a coherent nation, had a significant presence in western Asia, mostly along the southern coast of modern-day Turkey, a region known as Ionia. The Greeks living there maintained a decent autonomy despite falling under the dominion of Lydia, a powerful kingdom that held most of the territory in what is now eastern Turkey. However, when the Persians invaded Lydia and conquered it in the middle of the 6th century BCE, the Ionian Greeks became part of the Persian Empire, yet in their quest to maintain their autonomy, they proved difficult to rule.
Once the Persians had managed to conquer Lydia, they would have been interested in conquering Greece, as imperial expansion was one of the most important tasks of any ancient king. To do this, the Persian king, Darius I, enlisted the help of a man named Aristagoras, who was ruling as the tyrant of the Ionian city Miletus. The plan was to invade the Greek island of Naxos and begin subjugating more Greek cities and regions. However, Aristagoras failed in his invasion, and fearing that Darius I would retaliate by killing him, he called on his fellow Greeks in Ionia to rebel against the Persian king, which they did. So, in 499 BCE, much of Ionia was in open rebellion, an event known as the Ionian Revolt.
Athens and several other Greek city-states, mainly Eritrea, sent help to their fellow Greeks, but this proved to be folly as Darius I marched his armies into Ionia and by 493 BCE had ended the rebellion. But now, he was mad at the Greeks for their insurrection, and he had his eyes set on revenge.
Darius I Marches on Greece
About ten years before the Battle of Thermopylae, in an attempt to punish the Greeks for their support of the Ionian Revolt, Darius I gathered his army and marched into Greece. He went west through Thrace and Macedon, subjugating the cities he crossed. Meanwhile, Darius I sent his fleet to attack Eritrea and Athens. The Greeks put up little resistance, and Darius I managed to reach Eritrea and burn it to the ground.
His next objective was Athens – the other city which offered support to the Ionians – but he never made it. The Greeks chose to meet the Persians in battle, and they won a decisive victory at the Battle of Marathon, forcing Darius I to retreat back to Asia, effectively ending his invasion for the time being.
Many historians believe Darius I retreated to regroup for a second invasion, but he died before he ever had the chance. His son, Xerxes I, rose to the throne in 486 BCE, and after spending some time consolidating his power within the empire, he set out to avenge his father and force the Greeks to pay for their insubordination and insurrection, setting the stage for the Battle of Thermopylae. Below is a map detailing the movements of Darius I and his troops during this first invasion of Greece.
One of the reasons the Battle of Thermopylae is so famous is because of the preparations the Persians took to fight it. After seeing his father defeated by a smaller Greek force at the Battle of Marathon, Xerxes was determined to not make the same mistake. Xerxes drew upon his empire to build one of the largest armies the ancient world had ever seen.
Herodotus, whose account of the Greco-Persian Wars is the best primary source we have on these long wars, estimated the Persians had an army of nearly 2 million men, but most modern estimates put this number much lower. It’s far more likely the Persian Army was made up of around 180,000 or 200,000 men, which is still an astronomical number for ancient times.
Most of Xerxes’ army was made up of conscripts from around the empire. His regular army, the well-trained, profession corps known as the Immortals, totaled just 10,000 soldiers. They were so named because royal decree required this force always have 10,000 soldiers, meaning fallen soldiers were replaced one-for-one, keeping the force at 10,000 and giving the illusion of immortality. Up until the Battle of Thermopylae, the Immortals were the premier fighting force in the ancient world. Here’s a carving of what the Immortals may have looked like in ancient times:
The rest of the soldiers Xerxes took with him to Greece came from other regions of the empire, mainly Media, Elam, Babylon, Phoenicia, and Egypt, among many others. This is because when civilizations were conquered and made part of the Persian empire, they were required to give troops to the imperial army. But this also created a situation where people were forced to fight, at times against their will. For example, during the Battle of Thermopylae, the Persian army consisted partly of Ionian Greeks who had been forced to fight as a result of losing their rebellion. One can only imagine how motivated they really were to kill their countrymen at the bequest of their imperial overlord.
However, as impressive as the size of Xerxes’ army was, the preparations he undertook for his invasion are perhaps even more remarkable. To begin, he built a pontoon bridge across the Hellespont, the strait of water from which one accesses the Sea of Marmara, Byzantium (Istanbul), and the Black Sea. He did this by tying ships side-by-side across the entire stretch of water, which allowed his troops to easily cross from Asia into Europe while also avoiding Byzantium. This would have significantly cut down the amount of time required to make this journey.
Furthermore, he set up marketplaces and other trading posts all along the route he was planning to take to make it easier to supply his massive army as it proceeded west into Europe. All of this meant that Xerxes and his army, although it didn’t mobilize until 480 BCE, ten years after Darius I invaded and six years after Xerxes took the throne, was able to quickly and easily march through Thrace and Macedon, meaning the Battle of Thermopylae would be fought before the end of the year.
After defeating Darius I at the Battle of Marathon, the Greeks rejoiced but they did not relax. Anyone could see that the Persians would be back, and so most went about preparing for round two. The Athenians, who had led the fight against the Persians the first time around, began building a new fleet using silver they had recently discovered in the mountains of Attica. However, they knew it was unlikely they would be able to fend off the Persians on their own, so they called on the rest of the Greek world to come together and form an alliance to fight the Persians.
This alliance, which was made up of the major Greek city-states at the time, mainly Athens, Sparta, Corinth, Argos, Thebes, Phocis, Thespiaea, etc., was the first example of a pan-Hellenic alliance, breaking up centuries of fighting amongst the Greeks and planting the seeds for a national identity. But when the threat posed by the Persians ended, this sense of camaraderie also disappeared, but the Battle of Thermopylae would go on to serve as a reminder for what the Greeks could do when they worked together.
The alliance was technically under the direction of the Athenians, but the Spartans also played a key role largely because they had the largest and most superior land force. However, the Athenians were responsible for putting together and directing the Allied navy.
Greek soldiers at the time were known as hoplites. They wore bronze helmets and breastplates and carried bronze shields and long, bronze-tipped spears. Most hoplites were regular citizens who were required to buy and maintain their own armor. When called upon, they would mobilize and fight to defend the polis, which would have been a great honor. But at the time, few Greeks were professional soldiers, except for the Spartiates, who were highly-trained soldiers that ended up having a significant impact on the Battle of Thermopylae. Below is an engraving of a hoplite (left) and a Persian soldier (right) to give an idea of what they might have looked like.
The 300 Spartans
Although the above scene from the 2006 movie 300 is fiction and likely exaggerated, the 300 Spartans who fought the Battle of Thermopylae have gone down in history as one of the most fearsome and elite fighting forces to have ever existed. This is likely an exaggeration, but we should not be too quick to downplay the superior fighting skills of Spartan soldiers at the time.
In Sparta, being a soldier was considered a great honor, and all men, except for the first born of a family, were required to train at Sparta’s special military school, the agoge. During this training, Spartan men learned not only how to fight but also how to trust in and work with one another, something that proved to be rather effective when fighting in the phalanx. The phalanx was a formation of soldiers set up as an array that when combined with the heavy armor worn by hoplites proved to be nearly impossible to break. It was instrumental to the Greeks’ success against the Persians.
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All of this training meant that the Spartan soldiers, also known as Spartiates, were one of the world’s premier fighting force at the time. The 300 Spartans who fought at the Battle of Thermopylae had been trained at this school, but they are not famous because they were good soldiers. Instead, they’re famous because of how they got to the battle.
The story goes that Xerxes, as he made his way into Greece, sent envoys to the still free Greek cities offering peace in exchange for tribute, which the Spartans of course refused. However, all of this was happening during the Carneia, which was a festival dedicated to the god Apollo. It was the most important religious event on the Spartan calendar, and Spartan kings were strictly forbidden from going to war during this celebration.
However, Leonidas knew to do nothing doomed his people to almost certain death. As a result, he consulted the Oracle anyway, and he was denied permission to summon an army and go to war, leaving him with the tremendous dilemma between appeasing the gods and defending his people.
Outright denial of the will of the gods was not an option, but Leonidas also knew remaining idle would allow his people, and the rest of Greece, to be destroyed, which was also not an option. So, instead of mobilizing his entire army, Leonidas gathered 300 Spartans and organized them into an “expeditionary” force. In this way, he was technically not going to war, but he was also doing something to hopefully stop the Persians. This decision to ignore the gods and fight anyway has helped enshrine Leonidas as the epitome of a just and loyal king who felt truly indebted to his people.
The Battle of Thermopylae
The Greek alliance originally wanted to confront the Persians in Thessaly, the region just to the south of Macedon, at the Vale of Tempe. The Battle of Marathon had shown the Greeks they would be able to defeat the Persians if they could force them into tight areas where their superior numbers no longer mattered. The Vale of Tempe provided them with this geographical advantage, but when the Greeks got word that the Persians had learned of a way to go around the vale, they had to change their strategy.
Thermopylae was chosen for a similar reason. It was directly on the path of the Persians’ southward advance into Greece, but the Pass of Thermopylae, which was protected by mountains the west and the Gulf of Malias to the west, was just 15m wide. Taking up a defensive position here would bottleneck the Persians and help to level the playing field.
The Persian army was accompanied by its massive fleet, and the Greeks had chosen Artemisium, which lies to the east of Thermopylae, as the place to engage with the Persian contingency of ships. It was an ideal choice because it gave the Greeks the chance to stop the Persians before they could advance south to Attica, and also because it would allow the Greek navy the chance to prevent the Persian fleet from sailing to Thermopylae and outflanking the Greeks fighting on land.
By the end of August, or perhaps beginning of September 480 BCE, the Persian army was nearing Thermopylae. The 300 Spartans were joined by three to four thousand soldiers from the rest of the Peloponnese, cities such as Corinth, Tegea, and Arcadia, as well as another three to four thousand soldiers from the rest of Greece, meaning a total of around 7,000 men were sent to stop an army of 180,000.
That the 300 Spartans had significant help is one of the parts of the Battle of Thermopylae that has been forgotten in the name of mythmaking. Many like to think these 300 Spartans were the only ones fighting, but they weren’t. However, this does not take away from the fact that the Greeks were severely outnumbered as they took up their positions at Thermopylae.
The Greeks and Persians Arrive
The Greeks made it to the pass first, but the Persians arrived shortly thereafter. When Xerxes saw how small the Greek force was, he allegedly ordered his troops to wait. He figured the Greeks would see just how outnumbered they were and eventually surrender. The Persians held off their attack for three whole days, but the Greeks showed no signs of leaving.
During these three days, a few things happened that would have an impact on the Battle of Thermopylae as well as the rest of the war. First, the Persian fleet was caught in a wicked storm off the coast of Euboea that resulted in the loss of around one-third of their ships.
Second, Leonidas took 1,000 of his men, mainly people from the nearby city of Locris, to guard the relatively unknown passageway that circumvented the Pass of Thermopylae. At the time, Xerxes did not know this back route existed, and Leonidas knew his learning of it would doom the Greeks. The force stationed up in the mountains was set to serve not only as a line of defense but also as a warning system that could alert the Greeks fighting on the beaches in the event the Persians found their way around the pass. With all of this done, the stage was set for the fighting to begin.
Day 1: Xerxes is Rebuffed
After three days, it became clear to Xerxes the Greeks were not going to surrender, so he began his attack. According to sources, he sent his army in waves of 10,000 men, but this did not do much. The pass was so narrow that most of the fighting took place between just a few hundred men in close quarters. The Greek phalanx, along with their heavier bronze armor and longer spears, stood strong despite being so hopelessly outnumbered.
Several waves of 10,000 Medes were all beaten back. In between each attack, Leonidas rearranged the phalanx so that those who had been fighting would be given a chance to rest and so that the front lines could be fresh. By the end of the day, Xerxes, likely irritated that his soldiers could not break the Greek line, sent the Immortals into battle, but they too were rebuffed, meaning that the first day of battle would end in failure for the Persians. They returned to their camp and waited for the next day.
Day 2: The Greeks Hold but Xerxes Learns
The second day of the Battle of Thermopylae was not all that different from the first in that Xerxes continued to send his men in waves of 10,000. But just as on the first day, the Greek phalanx proved to be too strong to beat, and the Persians were once again forced to return to camp having failed to break the Greek lines.
However, on this second day, in the late afternoon or early evening, something happened that would turn the tables of the Battle of Thermopylae in favor of the Persians. Remember that Leonidas has dispatched a force of 1,000 Locrians to defend the second route around the pass. But a local Greek, who was likely trying to win over Xerxes’ favor in an attempt to receive special treatment after their victory, approached the Persian camp and alerted them to the existence of this secondary route.
Seeing this as his opportunity to finally break the Greek line, Xerxes sent a large force of Immortals to find the pass. He knew that should they be successful, they would be able to get in behind Greek line, which would have allowed them to attack from both the front and back, a move that would have meant certain death for the Greeks.
The Immortals traveled in the middle of the night and reached the entrance to the pass sometime before daybreak. They engaged with the Locrians and defeated them, but before the fighting began, several Locrians escaped through the pass to warn Leonidas that the Persians had discovered this critical weak point.
At Artemisium, the Athenian-led navy was able to inflict heavy damages on the Persian fleet by luring them into tight corridors and using their more agile ships to defeat the Persians. However, once again, the Persian numbers were too great and the Greek fleet was in trouble. But before retreating, an envoy was sent to Thermopylae to see how the battle was transpiring, for they did not want to abandon the fight altogether and leave the right flank of the Greek force at the pass exposed.
Day 3: The Final Stand of Leonidas and the 300 Spartans
Leonidas got word that the Persians had found the route around Thermopylae at dawn on the third day of battle. Knowing full well that this meant their doom, he told his soldiers it was time to depart. But not wanting to expose those retreating to the Persian advance, Leonidas informed his troops that he would remain with his force of 300 Spartans, but that all others could leave. Nearly everyone took him up on this offer except for around 700 Thebans.
Much legend has been attributed to this decision made by Leonidas. Some believe it was because during his trip to the Oracle before the battle began he was given a prophecy that said he was going to die on the battlefield if he did not succeed. Others attribute the move to the notion that Spartan soldiers never retreated. However, most historians now believe he sent off most of his force so that they could rejoin with the rest of the Greek armies and live to fight the Persians another day.
This move ended up being a success in that it allowed around 2,000 Greek soldiers to escape. But it did also result in the death of Leonidas, as well as his entire force of 300 Spartans and 700 Thebans.
Xerxes, confident he would now win the Battle, waited until the late afternoon to give his Immortals the chance to make it through the pass and advance on the remaining Greeks. When he finally attacked, he was able to win a decisive victory. After Leonidas was killed, the Greeks attempted to recover his body, but they failed. It wasn’t until weeks later that they were able to get it, and when they returned it to Sparta, Leonidas was enshrined as a hero. Meanwhile, receiving word that the Persians had found a way around the Pass of Thermopylae, the Greek fleet at Artemisium turned around and sailed south to try and beat the Persians to Attica and defend Athens.
This story of Leonidas and the 300 Spartans is one of bravery and valor. That these men were willing to stay behind and fight to the death speaks to the spirit of the Spartan fighting force, and it reminds us of what people are willing to do when their homeland and very existence are threatened. Because of this, the Battle of Thermopylae has remained in our collective memories for well over 2,000 years. Below is a bust of a Greek hoplite found at the Athena temple in Sparta. Most believe it is made from Leonidas’ likeness.
Battle of Thermopylae Map
Geography played an important role in the Battle of Thermopylae, as it does in nearly any military conflict. Below are maps that show not only what the Pass of Thermopylae looked like but also how the troops moved around throughout the three days of fighting.
After the Battle of Thermopylae, things did not look good for the Greeks. Xerxes marched his armies further south, ransacking much of the Euboean peninsula and eventually burning an evacuated Athens to the ground. Most of the Athenian population had been taken to the nearby island of Salamis, and it looked as though this would be the site of a potentially decisive victory for the Persians.
However, Xerxes made an error by following Greek ships into the narrow straits of Salamis, which once again neutralized his superior numbers. This move resulted in a resounding victory for the Greek fleet, and Xerxes, seeing now that the invasion was taking longer than he’d expected, and that it might not succeed, left the frontline and returned to Asia. He left his top general, Mardonius, in charge of carrying out the rest of the attack.
Plataea: The Deciding Battle
The Greeks had chosen the Isthmus of Corinth as their next point of defense, which provided similar advantages as the Pass of Thermopylae, although it left Athens in Persian-controlled territory. After seeing what the Greeks had managed to do at the Battle of Thermopylae, and now without a fleet to support his invasion, Mardonius was hoping to avoid a direct battle, so he sent envoys to the leaders of the Greek alliance to sue for peace. This was rejected, but the Athenians, angry at Sparta for not contributing more troops, threatened to accept these terms if the Spartans did not increase their commitment to the fight. Fearful of Athens becoming a part of the Persian empire, the Spartans pulled together a force of around 45,000 men. Part of this force was made up of Spartiates, but the majority were regular hoplites and helots, Spartan slaves.
The scene of the battle was the city of Plataea, and due to the Spartan contribution of troops, both sides were roughly equal. Initially a stalemate, the Battle of Plataea took place when Mardonius misinterpreted a simple troop movement as a Greek retreat and decided to attack. The result was a resounding Greek victory, and the Persians were forced to turn and run for Asia, fearing that the Greeks would destroy their bridge at the Hellespont and trap them in Greece.
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The Greeks did follow, and they won several victories throughout Thrace, as well as the Battle of Byzantium, which took place in 478 BCE. This final victory officially drove the Persians from Europe and removed the threat of Persian invasion. The Greco-Persian Wars would continue for another 25 years, but there was never another battle fought on Greek territory between the two sides.
While the Battle of Thermopylae has gone down in history as one of the most famous battles in the history of the world, it was really just a small part of a much larger conflict. However, the impossible odds the Greeks faced going into the battle combined with the legends surrounding Leonidas and the 300 Spartans has helped turn this battle and its famous last stand into a momentous event in human history.
But we should also be wary of underestimating the impact of this battle. The Battle of Thermopylae proved to the Greeks once again that, in the right terrain, their hoplites and phalanx could beat a Persian army of any size. This provided the Greeks with a winning strategy for much of the rest of the Greco-Persian Wars. But perhaps the real significance of the Battle of Thermopylae was the role it played in shaping human history. The Greeks have had a tremendous influence on the development of world culture, and had it not been for their valiant stands against the Persians in 490 and 480 BCE, who knows what our world today would look like.
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