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. About a tenth of the Greek city-states joined the 'Allied' effort; most remained neutral or submitted to Xerxes.
The invasion began in spring 480 BC, when the Persian army crossed the Hellespont and marched through Thrace and Macedon to Thessaly. The Persian advance was blocked at the pass of Thermopylae by a small Allied force under King Leonidas I of Sparta; simultaneously, the Persian fleet was blocked by an Allied fleet at the straits of Artemisium. At the famous Battle of Thermopylae, the Allied army held back the Persian army for three days, before they were outflanked by a mountain path and the Allied rearguard was trapped 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.
After Thermopylae, all of Euboea, Phocis, Boeotia and Attica fell to the Persian army, which captured and burnt Athens. However, a larger Allied army fortified the narrow Isthmus of Corinth, protecting the Peloponnesus from Persian conquest. Both sides thus sought a naval victory that might decisively alter the course of the war. The Athenian general Themistocles succeeded in luring the Persian navy into the narrow Straits of Salamis, where the huge number of Persian ships became disorganised, and were soundly beaten by the Allied fleet. The Allied victory at Salamis prevented a quick conclusion to the invasion, and fearing becoming trapped in Europe, Xerxes retreated to Asia leaving his general Mardonius to finish the conquest with the elite of the army.
The following spring, the Allies assembled the largest ever hoplite army and marched north from the Isthmus to confront Mardonius. At the ensuing Battle of Plataea, the Greek infantry again proved its superiority, inflicting a severe defeat on the Persians and killing Mardonius in the process. On the same day, across the Aegean Sea an Allied navy destroyed the remnants of the Persian navy at the Battle of Mycale. With this double defeat, the invasion was ended, and Persian power in the Aegean severely dented. The Greeks would now move to the offensive, eventually expelling the Persians from Europe, the Aegean Islands and Ionia before the war finally came to an end in 449 BC with the Peace of Callias.
Sources
The main source for the Great Greco-Persian Wars is the Greek historian Herodotus. Herodotus, who has been called the 'Father of History', was born in 484 BC in Halicarnassus, Asia Minor (then under Persian overlordship). He wrote his 'Enquiries' (Greek—Historia; English—(The) Histories) around 440–430 BC, trying to trace the origins of the Greco-Persian Wars, which would still have been relatively recent history (the wars finally ending in 450 BC). Herodotus's approach was entirely novel, and at least in Western society, he does seem to have invented 'history' as we know it. As Holland has it: "For the first time, a chronicler set himself to trace the origins of a conflict not to a past so remote so as to be utterly fabulous, nor to the whims and wishes of some god, nor to a people's claim to manifest destiny, but rather explanations he could verify personally."