Leonidas was born around 530 to 500 BC, and he was one of the sons of the Spartan king, Anaxandridas. Since his early childhood he was training to become a Hoplite Warrior. Hoplite Warriors were soldiers/citizens who were armed with a round shield, a spear, and an iron short sword. And this is what he originally intended upon being. (Leonidas, History, A&E)
All children who were born in Sparta were put into military training at the young age of 7. They were taught that they would come home after a battle either with their shield or on it, implying either coming home successful after battle or dead and carried on their shield. Since Leonidas was initially not to become king he anticipated becoming a general in the army. So because he became the king he was not only a military general now but he was the military leader as well as the political leader. (Leonidas, Humanities360.)
Anaxandridas died on 520 BC, and Cleomenes ruled from 520 or around 516 BC to 490 BC. In 489 BC he was considered insane by his people, and then deemed unfit as ruler. He was deemed the aforementioned due to the fact that he had been discovered plotting against his co-king. He had done this most likely to get complete power of Sparta. Although his death was ruled a suicide many modern historians dispute against this and say that they can’t be sure about it. (Cleomenes)
Not to incredibly much is known about Leonidas’ early life because he was not originally first in line royalty. He was still seen as high up in the chain of command but just not constantly monitored by people. Ten years after the battle of Marathon in 490 BC Xerxes, who was the son of Darius, had assembled a great army of around twenty-five million men completed with a great navy and ten thousand men elite soldiers known as “The Immortals” This Persian army was seen as a great threat to Greek because this was more than whatever the Greeks could possibly gather. The Spartans and Athens then looked past all their differences and came together to fight against the Persians. (Leonidas, Encycolpedia of World Biography)
Before he had gone to battle he had gone to the Oracle and asked for a prophecy concerning the Persian invasion. The oracle told him that Sparta would be destroyed or that he must be sacrificed in order to save Sparta. (Leonidas, Wikipedia)
In letters that Plutarch found he recorded a conversation of a few letters that they were sending back and forth to eachother the letters started with Xerxes saying that Leonidas was going against God because He had chosen Xerxes as the sole ruler of Greece. Leonidas replied saying that he would rather die than Greece having Xerxes as sole ruler. In the next letter Xerxes told Leonidas to hand over their arms. Leonidas then ended the conversation with “Come and take them” (Leonidas, About.com)
Leonidas had joined with all the Greeks including the Athenians at The Mountains of Thermopylae, when they were up there...