In 490 B.C.E.Darious sent messengers to ask for earth and water but they refused. Darious was mad so he sent a large army across the Aegean Sea to Greece. Athenians and their allies had to face the Persians Alone. Greeks won.
Battle of Plataea
After King Darious died his son king Xerxes organized another attack. He put together a huge army with more than 180,000 soldiers. in 480 B.C.E. Spartans worked hard and legend says they fought until their swords broke then they fought with their hands.
Citizens boarded ships when they heard news of the slaughter at Thermopylae. They left in a hurry and left their pets. One loyal dog swam and followed the boat.
Small greek empire worked to fight the big greek empire