In 490 B.C.E, the mighty nation of Persia, led by Darius the Great, tried to invade Greece in a series of battles taking place in mainland Greece, Asia minor, Cyprus, and Egypt. This was called the Greco- Persian wars. It all started with the Ionia and the Ionian rebellion. In 545, the persian empire annexed Ionia. None of the Greek city- states wanted to try to attempt an armed excursion in defense of Ionia. They did ,however, send a messenger to Cyrus, the Persian emperor at the time, giving him a warning to stay away from Greece. Upon getting the message, the Persian emperor only responded, " Who are the Spartans?". The Ionians decided to revolt against the Persian empire, and thats whats started the Greco- Persian wars. The battle of Thermopylae was preluded by the battle of Marathon. This was a significant battle because the Greeks won, and that victory proved that they can out fight the Persian forces, they came into the battle of Thermopylae with a sense of confidence and they new they could compete and win.