The document summarizes key events in the Persian Wars between Greece and Persia:
1) Persia conquered Ionia with the Greeks helping in a rebellion, angering the Persian King Darius.
2) At the Battle of Marathon, the Athenians defeated a large Persian invasion force that landed in Greece.
3) Xerxes, Darius' son, sought revenge on Greece and invaded with a huge army, conquering Northern Greece.
4) At Thermopylae, 300 Spartans held off the Persians for three days, allowing the Athenians to evacuate, but were eventually defeated when the Persians found an alternative route.