King Leonidas I, whose name meant "lion-like," was king of Sparta between 488BC and 480BC. He is best known to history as the commander of the Spartan army at the Battle of Thermopylae during the Persian Wars. The story of his sacrifice has been an inspiration to generations and was recently brought to the big screen by Gerard Butler in the movie 300 which was based on a graphic novel of the same name by Frank Miller.
Leonidas was born around 520BC to King Anaxandridas II, a descendant of Hercules. Anaxandridas had two wives, so Leonidas had a half-brother, Cleomenes I, in addition to his younger brother Cleombrotus I and his older brother Dorieus. Although Cleomenes succeeded Anaxandridas after his death because he was probably the firstborn of the four, he was the son of Anaxandridas' second wife, so his claim to the throne was not entirely solid. The throne could have gone to Dorieus as Anaxandridas' oldest son by his first marriage.
Whether it was because he feared him as a rival or because he really did have an interest in foreign expansion, Cleomenes supported Dorieus in several foreign expeditions. Fortunately for Cleomenes, Dorieus was killed on one of these expeditions. Dorieus was not the only rival that Cleomenes faced, however. One of his greatest political enemies was his co-king Demartus. The two Spartan kings frustrated each others plans for several years until both were finally forced into exile. Demartus found his way to Persia where he became an adviser to Xerxes. It was he who cautioned Xerxes not to underestimate the Spartans at the Battle of Thermopylae.
Cleomenes, on the other hand, was eventually allowed to come home. He was soon accused of being insane, however, so he was put into prison and chained under the orders of his half-brothers, Leonidas and Cleombrotus. Before long, he was found dead with pieces of flesh cut from his body and a bloody knife on the floor next to him. Whether he was murdered or committed suicide remains as much of a mystery to historians as whether or not he was actually insane.
Cleomenes had no children except for his daughter Gorgo, who was already married to Leonidas, so Leonidas became king in 489BC or 488BC. He inherited a city-state in danger of conquest. For many years, the Persian Empire had exerted a powerful influence on Greece. Make city-states, especially in the region of Ionia, had already submitted to Persian rule and as recently as 491BC, Persia's King Darius had attempted to conquer Greece outright.That the Greeks defeated the Persians at the Battle of Marathon in 490BC did little to ameliorate the Persian threat. Leonidas and others knew that they could always return.
That is just what the Persians did. Darius died in 486BC and was succeeded by his son Xerxes. After making extensive preparations, Xerxes set out to conquer the Greeks in 480BC. Like his father, he sent messengers to the various Greek city-states demanding a tribute of earth and water to signify submission to Persia. Most accepted the offer, but Sparta and a few others did not. The Athenians killed the messengers outright while the Spartans threw them down a well instructing them "dig it out for yourselves."
Soon, Xerxes left Babylon at the head of the enormous army he had been preparing for years. Although modern historians cannot be sure how big it was, the army probably contained several hundred thousand men. Whatever their numbers, the Persians greatly outnumbered the Greeks in Sparta, Athens, and the other resisting city-states. This was an advantage they retained throughout their campaign in Greece.
The resisting city-states put aside their differences to work together for their common defense. Their only hope in the face of such overwhelming numbers was to meet the Persians at a key choke point. After missing their opportunity to stop the Persians at the Vale of Tempe, the Greeks decided that Thermopolyae would be the place to block the Persian advance into southern Greece. There, the terrain was so narrow that it would prevent anything but a small part of the Persian army from engaging the Greeks at any given time. At Thermopolyae, Persia's numbers count for very little.
Unfortunately, Leonidas was forced to meet the Persians without the use of the full Spartan army. Whether it was intentional or not, Xerxes had planned his invasion during important religious festivals for the Greeks. The Athenians were celebrating the Olympic Games in honor of Zeus and the Spartans were celebrating the Carneian festival in honor of Apollo as the Persians threatened to conquer them. But because Spartan law forbid the army from fighting during the festival, Leonidas was only able to take his personal bodyguard to fight with him at Thermopylae. Athens was also unable to commit a full force and what troops it did send had to be used to stop the Persian navy.
It was believed that a small Greek force at Thermopylae would be sufficient to hold the Persians long enough for the Greek allies to mobilize theirfull forces after celebrating their various religious festivals. With the addition of troops from several smaller city-states, the Greek force probably number about 7,000, so they did have a reasonable chance of holding the Persians for a while. Again, the terrain of Thermopylae would be their biggest asset.
Nevertheless, Leonidas clearly realized that he would not return from Thermopylae. Partially, that was his intention. The oracle at Delphi had already prophesied that Sparta would either mourn the loss of its city, or one of its kings who was descended from Hercules. Therefore, Leonidas believed that if he went with a small force and sacrificed himself, Sparta would be saved. Obviously, he would have probably to take the whole army with him, but he had to obey Sparta's laws. Therefore, he took only a personal bodyguard consisting of 300 of his best warriors, all with born sons to carry on their family names.
That he did not plan to return home can seen in his final words to his wife, Gorgo. According to Plutarch, before Leonidas left for Thermopylae, Gorgo asked him what he wanted her to do. He said, "marry a good man that will treat you well, bear him children, and live a good life." He knew he was not coming home. He would go to Thermopylae and sacrifice himself to save Sparta. He was right because Gorgo never saw him again.
The Greek coalition army was successful at holding the Persian advance for several days. It was not until a local named Ephialtes told the Persians about a path around the Greek lines that the Greeks were doomed. Surrounded, they had no chance at all. Leonidas therefore sent most of the army away, remaining only with his 300 Spartans, their slaves, and a few others. In total, this force probably numbered about 2,000. With the exception of some Thebans who surrendered, all of the remaining Greeks were killed.
Thermopylae may have been a defeat for the Greeks, but it was no great victory for the Persians. It is hard to say exactly how many men the Persians lost, but modern estimates put the figure around 20,000 men. Further, the battle gave the Athenians enough time to evacuate Athens and flee to the island of Salamis. Because of the men and time the Persians lost at the Battle of Thermopylae, the Greeks were able to defeat them in a naval battle at Salamis and later at a land battle at Platea. Persia never again attempted to invade Greece. It was the beginning of the end for the Persian Empire and the beginning of great things in Greece.
According to Herodotus, Xerxes ordered Leonidas' head to be cut off and put on a stake and his body crucified. Eventually, his body was returned to Sparta where it was buried. He was succeeded by his son Pleistarchus who ruled with the help of a regent for several years before ruling exclusively as the 18th in the Agiad line of Spartan kings.