Persian Wars
Also called: Greco-Persian Wars
Achaemenid Persia invaded Greece three times, but an alliance of city-states led by Athens and Sparta drove it back at Marathon, Salamis and Plataea.

Jacques-Louis David · Public domain · Source
In 499 BC the Greek cities of Ionia on the west coast of Asia Minor, under Persian rule, revolted with Athenian help. Having crushed the revolt, Darius I turned on mainland Greece. The first expedition, in 492 BC, turned back after its fleet was wrecked in a storm, and the second was defeated by the Athenians at Marathon in 490 BC.
In 480 BC Darius’ son Xerxes invaded with a huge army. The Spartan king Leonidas died holding the pass of Thermopylae and Athens was burned, but the Greek fleet under Themistocles smashed the Persian navy in the straits of Salamis. The next year the Greeks won again at Plataea and Mycale, and the Persians withdrew.
The Greeks took pride in having defended their freedom against a vast eastern empire. The poor citizens who had rowed the warships gained a stronger voice, which helped bring Athenian democracy to its full form, and Athens entered its golden age as leader of the Delian League. Herodotus recorded the war in his Histories, earning the title “father of history”.