In 490BC, the Persian King Darius I sent an amphibious expedition into the Aegean, only to be defeated by a far smaller force of Athenians at the Bay of Marathon.
As Achaemenid Emperor, leader of the most powerful state of his time, King Darius I was sovereign over 21 million square miles and more. He had more to deal with than a handful of malcontents in the Peloponnese. At the moment, Darius had an Egyptian revolt to put down, but the “King of Kings’” would be back. He had a score to settle with the Greeks. King Darius died before he was through, so it was that the Persian King Xerxes would return to finish what his father had begun, ten years before.
In 480BC, news of a massive Persian army on the move reached Lacedaemonia, principal region of the Spartan state. De facto military leaders of the Greek alliance, the Spartans were then celebrating the religious festival of Carneia. Lacedaemonian law forbade military activity at this time, the same reason the Spartans had shown up late at Marathon, ten years earlier.
Spartan leaders went to the Temple of Apollo at Delphi, for advice.

The Oracle at Delphi was a seer, usually selected from among epileptics, as the Greeks believed seizures were evidence that the sufferer was in touch with the Gods. A careful ritual was observed, before the Priestess would speak. First she would bathe in the Castalian Spring, before drinking from another stream. A priest would then pour ice water over a goat, to determine the presence of Apollo. The goat’s shivering was understood to indicate that the God was present, and that he had invested his powers in the Oracle. If the signs were fortuitous, the Oracle would then inhale the gas emitted from a chasm near the temple. With volcanic gasses rising from the ground beneath her, the “Pythia” would then mount to the Tripod. Only then would she speak.

“Hear your fate”, said the oracle, “O dwellers in Sparta of the wide spaces. Either your famed, great town must be sacked by Perseus’ sons, or, if that be not, the whole land of Lacedaemon shall mourn the death of a king of the house of Heracles. For not the strength of lions or of bulls shall hold him, strength against strength; for he has the power of Zeus, and will not be checked until one of these two he has consumed.”
For King Leonidas of Sparta, the meaning was clear. He himself would have to die to fulfill the Oracle’s prophesy.
Leonidas gathered a small blocking force of 300 Spartan Peers, all of them “Sires”. This was understood to be a suicide mission. Leonidas wanted only those warriors who would leave behind, a son.
Several Greek city states were technically at war with one another in 480BC, but that was dropped, as preparations were made for a two-pronged defense. An allied Greek navy would meet the Persian triremes at the straits of Artemisium while an army of Hoplites, Greek heavy infantry, would meet the Persian army at the narrow pass known as the “Hot Gates”. Thermopylae.

The 300 marched out at the head of an allied army of 7,000, to meet a Persian horde modern estimates put at 100,000 to 150,000. A native of Trachis told the Spartan General Dienekes, that Persian archers were so numerous their arrows would block out the sun. “Good”, replied the general. “Then we shall fight in the shade”.
When the overwhelming Persian army demanded the Spartans lay down their arms, Leonidas’ response was short and sweet. “Molon Labe”, he said. Come and get them.
The two armies collided on or about the 8th of September, 480BC. Thermopylae, a mountain pass delineated by the Phocian Wall on one side and the Aegean Sea on the other, measured the width of two carts abreast, negating the Persian numerical advantage. Great piles of Persian dead choked the pass by the end of the 9th. Nothing that Xerxes could throw at the Greek heavy infantry could break their phalanx.
A traitor to his people then rose among the local population, Ephialtes of Trachis, who led the Persians through a narrow path to come around behind the Greek line.

Knowing he was betrayed and would soon be surrounded, Leonidas sent most of the allied soldiers away. They would be needed for the battle yet to come.
On day three, King Leonidas was left with his 300 Spartans, 700 Thespian allies and an unreliable contingent of 400 Thebans. True to form, the Theban band defected en masse to the Persian side, at the earliest opportunity. Still, the hordes of Xerxes were unable to break through the Greek line, even on two fronts. They backed off and rained down arrows from a distance, until no Greek was left standing.
Artemisium devolved into a meaningless stalemate, and yet the Greek alliance had demonstrated itself more than capable of standing up to the mightiest empire of its time. Athens, lacking the manpower to fight simultaneously on land and at sea, abandoned their city to be burned to the ground. The regrouped Greek Navy crushed the Persians at Salamis. The last Persian invader was driven off the Greek mainland the following August, following Greek victory at a place called Plataea.
Simonides’ famous encomium to the dead was inscribed on a commemorative stone at Thermopylae, atop a hill where the Greeks made their final stand. The original stone is gone now, but the epitaph was engraved on a new stone in 1955.
“Go tell the Spartans, stranger passing by, that here, obedient to Spartan law, we lie.”
