Themistocles was an Athenian commander of the fleet at the battle of Salami against Persians.
He did not defeat the Persians. The Persians were defeated in three battles - Themistocles was at one of them - Salamis where the commander was Spartan Eurybiades. Themistocles is credited with a successful ruse to split the Persian fleet which evened the size of the fleets, and proposing the battle be carried out in the confined waters in the strait at Salamis which gave the Greek fleet the opportunity to attack the flanks of the heavier Persian ships with their lighter ones.
The Persians were defeated by the Athenian Admiral Themistocles at the sea battle of Salamis and the Spartan general Pausanius defeated the Persian army led by Mardonius at the battle of Plataea .
At the battle of Marathon 490 BCE the Athenians defeated the Persians.
Figure it out
Notably , the battle of Marathon .
They did npt defeat Athens.
The overall Greek strategy was to thwart the Persian advance at the narrow pass of Thermopylae using a Spartan/Thespian/Theban blocking force , while at sea the Athenian Admiral Themistocles was to prevent Persian naval forces from outflanking the Greek land contingent by making an amphibious landing behind the Spartan King Leonidas and the Greeks . Themistocles was able to defeat the Persians at the sea battle of Salamis and the Greeks were able to withstand the Persian infantry assaults only to be outflanked on the land because the traitor Ephialtes had shown the Persians a way of outflanking the Greeks by showing the Persians a way around the pass of Thermopylae .h
Figure it out
The sea battle of Salamis.
Figure it out
Themistocles used 300 or so war ships to stop the Persians from coming in through the Artemisum Straight so they couldn't get behind the geek lines. The Persians realized that they could sail along the length of the island to get around the blockade, but Themistocles had anticipated tis and had a blockade there also.