The Achaemenid Emperor Xerxes I, after his accession, quickly initiated his preparations for an invasion of Greece, including the task of building two pontoon bridges across the Hellespont.
A congress of city states met, probably at Corinth, in 481 BC, and a confederate alliance of Greek city-states was formed, generally referred to as the Allies.
[5][6] In August 480 BC, after hearing of Xerxes' approach, a small Allied army led by Spartan King Leonidas I blocked the pass of Thermopylae.
According to Herodotus, the Spartans were at that time celebrating the festival of Hyacinthus, and delayed making a decision for ten days,[b][14] until they were persuaded of the danger to all of Greece if the Athenians surrendered.
The mountain slopes they had deployed on did not have access to freshwater, and carrying such quantities daily was logistically difficult and made them highly vulnerable to attacks by Persian cavalry.
[56] When Mardonius learned of the Spartan force marching to join the allied Greek army, he completed the destruction of Athens, tearing down whatever was left standing.
[20] Mardonius withdrew from Attica through the Decelea defile, passed by Sphendale, crossed the Parnes range,[57] encamped for a night at Tanagra and then marched to Skolos.
[48] Mardonius built a fortified encampment around 1.9 square kilometres (0.73 sq mi) in area on the north bank of the Asopos river in Boeotia,[48] thus covering the ground from Erythres past Hysiae and up to the lands of Plataea.
The army traveled on the Oenoe road via Panactum, the plains of Skourta and the eastern Pastra mountain,[59] across the passes of Mount Cithaeron and arrived near Plataea.
Masistius was flung off his horse and landed near the Athenian line, where the soldiers started stabbing him but were unable to kill him as he was wearing scale corslet armor underneath his clothes.
[66] Their morale boosted by this small victory, the Greeks moved forward, still remaining on higher ground, to a new position near the Asopos river which was more defensible and better watered.
On the eighth day after the arrival of the Persian and Greek armies at Plataea, heeding the advice of a Theban named Timagenes, Mardonius set up a lookout on the passes of Mount Cithaeron.
The Allied contingents in the centre began their movement late at night, and perhaps because they were not aware of the new terrain, ended up advancing 1.8 kilometres (1.1 mi) past the island to arrive at the Temple of Hera.
Pausanias then marched 3 kilometres (1.9 mi) to the north of modern Erythres, and the Greeks of the scattered center started to converge on his position, though the latter probably took longer to get into formation.
[102] The Persian Immortal lines were probably ten files deep, where sparabara were on the front wearing scaled iron corslets, armed with spears, bows and shields.
Travelling through the lands of Thessaly, Macedonia and Thrace by the shortest road, Artabazos eventually made it back to the Hellespont, though losing many soldiers to Thracian attacks, weariness and hunger.
[152][153] de Jong notes that the Greek soldiers had divided between themselves the "women, horses, talents, camels and yoke animals" captured from the Persian camp.
[156] She argues that this experience had attracted Pausanias to the luxurious Persian lifestyle and might have led to his medism, especially since he had claimed and received a greater share of the loot at Plataea.
[131] The historian Ellen Millender argues that the desire to acquire spoils and glory led to Spartan leaders initiating multiple endless wars, which destabilized Sparta.
[162] She argues that the battle of Plataea was an anomaly in the sense of the loot it begot, perhaps because Xerxes' royal tent, which had extensive supplies, was retained for Mardonius' stay and later plundered.
[188] He argues that these cavaliers could fire arrows and javelins at the Greeks without coming within the range of the latter's spears; and that the Persian infantry inflicted much damage on the Spartans, who did not have long-range weapons to counter and defend themselves.
He also observes how the Persians used their archers for area denial by putting the banks of the Asopos river within their arrows' range and thus cutting off the Greeks' source of fresh water.
He argues that the Greek strategy was to pull the Persians into a pitched battle, because the former were logistically constrained while managing their large army for long; and because they might have believed the terrain was advantageous for them.
Cawkwell argues that the reason for the Persian attack had been a shortage of supplies, since their food stocks were going to run out in a few days, which was also why Artabazos had advocated for retreating to Thebes.
The archaeologist Andreas Konecny argues that the Greek position near Mount Cithaeron had been very well suited for defence,[50] but they could not have defeated the Persians without fighting a pitched battle.
According to Konecny, there were two reasons the Greeks had to fight a pitched battle: because their phalanx armies were not suitable for a war of attrition or maneuver warfare, which the Persian invasion would transform into; and because they did not have the required logistical support.
[198] Konecny argues that if Mardonius had executed a proper systematic attack or if Artabazos had reinforced him earlier, the Persians might have won, or at least suffered fewer casualties.
[136] The historian John Francis Lazenby observes that the run-up to Plataea had resembled that at the Battle of Marathon in some ways; there was a prolonged stalemate in which neither side risked attacking the other.
[207] They argue that the Greeks formed a defensive line during the final battle, sent small groups out to provoke the Persians into breaking their formations, and only then did they start pushing like Classical hoplite phalanxes.
[212] The historian Peter Hunt notes that Herodotus did not state the casualties incurred by the perioikoi, and argues that they could not have emerged unscathed from the Persian arrow volleys.