After the Achaemenid Persian defeat under Darius at the Battle of Marathon ten years before, his son Xerxes decided, under pressure from his advisors, to invade Greece overwhelmingly by land with an accompanying supply fleet offshore. In the summer of 480 BCE, Xerxes’ Persian Army conducted the largest seaborne invasion of Europe until the Normandy landings in 1944, 2500 years later. And then in one of the engineering marvels of the ancient world, the Persians constructed two 1,300m pontoon bridges across the Hellespont (the modern Dardanelles) and marched the rest of his massive army across over a total of seven days and seven nights.

The Athenian General Themistocles suggested that the Greeks make a stand at the narrow pass at Thermopylae (or “Hot Gates”, named after a warm spring nearby) and the adjacent straits of Artemesium. The narrow confines of each would mitigate the Persians’ greater numbers. Themistocles, an Athenian, would lead the Greek navies at Artemesium, while King Leonidas of Sparta led the Greek armies. On his march to the pass, Leonidas collected various contingents from other Greek city states, but due to the Olympic Games, during which fighting is prohibited, he could only collect limited forces. Nonetheless he planned to delay the Persians long enough for the rest of the Greeks to mobilize after the games. From Sparta, he brought only his personal bodyguard of 300 hoplites, and 900 other squires and armed retainers. The remaining Spartan army would fight with the main Greek army when it formed. Along the march he collected 4000 hoplites and 3000 more armsmen from the city states of Phocia, Trachis, Arcadia, Corinthia, Tegea, Mantinea, Thebes, Thespia, Malia, and Locria.

On 19 August 480 BCE) the 400,000 strong Persian Army under Xerxes I arrived outside of the narrow pass of Thermopylae and met the 8000 Greeks under King Leonidas. A Trachian lamented that the Persians were so many that their arrows would blot out the sun. A Spartan file commander, Dienekes, responded, “Good, then we will fight in the shade.” Hoping that the show of force sufficiently cowed the Greeks, the Persian herald demanded Leonidas surrender his weapons in a show of subservience to Xerxes. Leonidas responded “Molon labe”, “Come and get them.”

It took three days for Xerxes to organize an assault and on 22 August he attacked. The Greeks were armored in their traditional heavy bronze breastplate, helmet, and greaves, and armed with a large bronze shield (hoplon), an 8 ft stabbing spear (dory) that they used overhand, and a short sword (xiphos). They fought in their traditional densely packed shoulder to shoulder formation called a “phalanx” which was amazingly effective in the narrow Thermopylae Pass. The Persians were many and varied and from different provinces of Near Eastern Asia but few were as heavily armed as the Greeks. The only equivalents in the Persian army were Thessalian hoplites from already conquered Greek city states who were forcibly conscripted during the Persian advance. Persian arms and armor were meant for speed, mobility, and ranged attacks in the deserts, steppes, and mountains of their homelands. They could not withstand the rigors of close quarters combat in the narrow valleys of Greece. Their cane arrows and javelins couldn’t pierce the bronze armor; and their cloth, wooden or leather armor, and wicker shields, provided no protection against the iron weapons. Furthermore, the Greeks were soldiers in the Western tradition and valued discipline and maintaining position where their large shields could protect the man next to him. The Persians were warriors in the Eastern tradition which valued the personal kill. The Persian warriors continually broke formation making them easier to kill by the disciplined mass of Greek spears. Even Xerxes’ own bodyguard, the elite Immortals, known so because they always maintained a number of 10,000 due to casualties immediately replaced, could not break the Greek phalanx. Leonidas and his small army held the pass against overwhelming numbers for two days under constant assault.

In the early hours of the third day, a Greek traitor named Ephaliates led the Immortals on a little known mountain track which out flanked Leonidas. The small Phocian force sent to hold it was pushed aside. That morning, the Greeks met to discuss the new situation, and only the Spartans and Thesbians volunteered to remain and fight. The Thebans also stayed, but Herodutus said it was against their will. The rest of the army fell back to join the Greeks mobilizing after the Olympic Games. That afternoon the Persians attacked from both sides of the pass and overwhelmed the remaining defenders. The Thebans, bitter rivals of both the Spartans and Athenians, surrendered to the Persians. Leonidas and the remaining Spartans and Thesbians fought to the death.

Over the next few weeks, Xerxes went on to conqueror Phocis, Boeotia, Euboea, and Attica, to include the city of Athens, which was sacked. However, the time bought with the lives of Leonidas’ Greek defenders at Thermopylae was well spent. In September, Themistocles lured Xerxes fleet into battle in the straits of Salamis, where the Persian navy was decisively defeated. With no way to supply his huge army in Greece, most of it returned to Persia, including Xerxes himself. Xerxes turned the army over to Mardonius, Xerxes most powerful advisor and the newly appointed Satrap of Greece. In 479 BCE, the combined armies of the remaining Greek city states under Leonidas’ nephew, the Spartan regent Pausanias, defeated Mardonius and the Persian army at the Battle of Plataea. The victories of Salamis and Plataea cemented Greek freedom from Persian domination to this day. The Greek experiment in democracy was not killed off in the cradle.