Greeks had been settled in Ionia which is on the coast of Anatolia. Then around 546 B.C. persians came and conquered the area But the Ionian Greeks revolted, then Athens sent ships and soldiers to their aid. King Darius The Great vowed to destroy the Athens in revenge.
Battle at Marathon
The Persians King Darius The Great won against the persians and he vowed to destroy them in revenge. The persians fleet carried 25,000 men across the Aegean Sea and landed northeast of Athens on the marathon which is a plain. 10,000 Athens charged at the persians. The persians wear light armor lacked land combat. The Greeks had won after several hours and the Persians had fled.
Athens won the battle. There city looked defenseless. Army leaders chose a young runner named Pheidippides to race back to Athens. He brought news to Athens talking about the persians defeat so that the Athenians wouldn't give up their city without a fight.
When Xerxes came to a narrow mountain pass at Thermopylae. 7,000 Greeks, 300 Spartans blocked his way. Xerxes assumed that his troops would easily push the Greeks aside. Xerxes didn't underestimate their fighting ability.
The Greeks stopped the persian advance for 3 days, only a traitors informing the persians about a secret path around the pass ended their brave stand. Fearing defeat, the Spartans valiant sacrifice all were killed. They made a great impression on all the Greeks.
Darius The Great's son and successor, Xerxes assembled on enormous invasion force to crush the Athens. The Greeks city-states agreed to fight the Persians, others thought it was wiser to let Xerxes destroy Athens and return home. Some Greeks even fought on the Persian side, Xerxes had no resistance as if marched down the eastern coast of Greece.