Themistocles lured Persia's huge navy into a strait too narrow to fight in
In 480 BC Athens had been evacuated and Xerxes's army held the city. The Greek fleet, badly outnumbered, sat off the island of Salamis. Themistocles then sent a message to the Persian king himself, tempting him into the cramped straits, where sheer numbers turned from strength into chaos and handed the Greeks a turning-point victory.
The war's roots lay in the Ionian Revolt of 499 to 494 BC, when Athens and Eretria backed Greek cities rebelling against Darius I. Darius vowed revenge. His envoys demanding earth and water as tokens of submission were executed in Athens and thrown down a well in Sparta, and his first invasion ended with the Athenian win at Marathon in 490 BC. His son Xerxes prepared something far larger, bridging the Hellespont with pontoons and cutting a canal behind Mount Athos, where a Persian fleet had been wrecked in 492 BC.
Athens, guided by Themistocles, had decided in 482 BC to build a big fleet of triremes, and in late 481 BC a congress at Corinth forged an alliance among cities that were in some cases still formally at war with one another. Their plan paired a land block at Thermopylae with a naval one at Artemisium. When Leonidas's force was outflanked after three days, the fleet pulled back too, Athenians fled to Troezen and Salamis, and Persians burned Thespiae and Plataea before entering the empty city. On the way, Themistocles left messages at watering places urging Ionian Greeks in the Persian fleet to defect or at least hang back.
Arguments followed on both sides. The Corinthian commander Adeimantus wanted to fall back and guard the Isthmus; Themistocles insisted that fighting in confined waters favoured the Greeks, and won. At Xerxes's council, Artemisia, queen of Halicarnassus, warned that attacking in the straits was needless risk, but Xerxes and Mardonius wanted a decisive clash. Reports of Greek divisions, possibly a deliberate ruse, reached Xerxes, and his ships rowed in to seal both exits. Crowded and disordered, they were beaten by a Greek line.
Xerxes withdrew to Asia with much of his army, leaving Mardonius behind, and the next year Persian forces lost at Plataea and Mycale. Persia never again tried to conquer mainland Greece, and from then on the Greek cities went on the offensive. Salamis was arguably the biggest naval battle of the ancient world.
Source: Battle of Salamis
