Western Democracy traces its roots to ancient Greece, a land of squabbling city-states. Amongst these warring city-states arose Athens, and a group of men who had a funny idea: citizens should get a say in who exactly got to rule them. Though initially imperfect in its implementation, that idea has since evolved to the free Democratic nations most of us live in today- but it could all have been lost to a single moment in history. today we're taking a look at another of the Greatest Battles in History: the battle of Thermopylae In 499 BC Greek cities which had been captured by the Persians in Asia Minor revolted against the brutal tyrants that had been placed to oversee them. In support of their conquered brethren, Athens and Eretria sent troops. Despite some major gains, several strategic mistakes cost the Greeks of Asia Minor their ultimate victory and the rebellion was put down. With Asia Minor back in the fold of the Persian Empire, the Persian king Darius I vowed to punish Athens and Eretria for their involvement, and saw the rest of the free cities of Greece as a threat to his empire. In 492 BC he launched an invasion of Thrace and Macedon, then sent heralds to the remaining Greek city-states demanding they accept Persian rule. Seeking to save themselves, many agreed- with the notable exceptions of Athens and Sparta. The Persian heralds in Athens were thrown into a pit, and their Spartan brethren followed suit by tossing theirs into a well. Enraged, Darius launched his invasion of mainland Greece and met with further success until an encounter against 10,000 Athenians in Marathon.