What was the major victory of the Persian War?

Answer 1

The battle on which the Greek defence against the Persian invasion turned was the sea-battle at Salamis. The Greek coalition needed to defeat the Persian navy so that it did not threaten the member city-states, forcing them to keep their armies at home defending their cities against seaborne invasion, and able to be picked off one by one by the Persian army. The Persians also relied on a supply fleet to maintain their army from Asia Minor as the Greek countryside was too poor to support the Persian army and cavalry.

The victory at Salamis meant that the remnant Persian navy was withdrawn to Asia Minor and half the Persian army had to be sent back too as it could not be fed during the winter without the Persian fleet to protect the supply ships. The following spring, with no naval threat to their home cities, the southern Greek cities sent out their armies to combine and defeat the half-remaining Persian army and its Greek allies at Plataea, so ending the invasion This all hung on the prior success at Salamis.