The second Persian invasion of Greece (480–479 BC) occurred during the Greco-Persian Wars, as King Xerxes I of Persia sought to conquer all of Greece. The invasion was a direct, if delayed, response to the defeat of the first Persian invasion of Greece (492–490 BC) at the Battle of Marathon, which ended Darius I's attempts to subjugate Greece.
After Darius's death, his son Xerxes spent several years planning for the second invasion, mustering an enormous army and navy. The Athenians and Spartans led the Greek resistance, with some 70 city-states joining the 'Allied' effort. However, most of the Greek cities remained neutral or submitted to Xerxes.
At the famous Battle of Thermopylae, the Allied army held back the Persian army for seven days, before they were outflanked by a mountain path and the Allied rearguard was trapped in the pass and annihilated. The Allied fleet had also withstood two days of Persian attacks at the Battle of Artemisium, but when news reached them of the disaster at Thermopylae, they withdrew to Salamis.