In 480 BC the Persians again invaded Greece, King Xerxes leading a huge army across from Anatolia, shadowed by a fleet of about 1,200 warships. Many of the southern Greek city-states banded together under Spartan leadership to stop him by land and sea. Coordinated attempts to block the advance of his army in the narrow pass of Thermopylae and hold up his fleet at Artemision failed when the Greek land forces were outflanked and forced to withdraw. A small Spartan and Thespiaean rearguard resisted heroically , but was overwhelmed.

The combined Greek fleet moved to the island Salamis, abandoning the cities of Thebes and Athens to the enemy. A prophecy urging the Athenians to put their faith in a wooden wall caused some of them to fortify their Acropolis with timber, but the majority agreed with the elected general Themistocles that their best hope lay in the city's 200 wooden, trireme warships, the largest contingent in the Greek fleet. After the evacuation of the Athenians to Salamis had been completed, the Greek fleet assembled in the bay on the eastern side of the island.

When the news came that the Acropolis of Athens had been occupied, the Spartan commander Eurybiades ordered his captains to withdraw under cover of darkness to a more defensible position on the Isthmus of Corinth, but changed his mind later that night and the Greeks sailed out to confront the Persians the next morning. Herodotus claims that Themistocles sent a secret message to warn Xerxes that the Greeks were about to withdraw, causing him to send ships around Salamis to cut off the Greeks' retreat and forcing Eurybiades to risk a battle.

This story is a highly dubious one, assuming as it does that King Xerxes and his commanders would trust such a message, and that Themistocles would have thought it advantageous to provoke a Persian attack. It is more likely that the Persians planned to surround the Greeks, as they had attempted once before at Artemision. Their aim would have been to drive the Greek ships northwards and westwards out of the narrow channel between Salamis and the mainland, into the open waters of the Bay of Eleusis, and attack them from two sides. For this purpose Xerxes dispatched 200 Egyptian ships in the early evening to sail right round Salamis and come at the Greeks from the direction of Eleusis. He also sent a flotilla to cruise the waters around the southern end of the island, while his main fleet (around 600 ships) moved into position at the eastern approaches to the narrow straits, ready to advance at dawn.

The Greeks were made aware of these maneuvers by Aristeides, an exiled Athenian politician who had returned to join in the fight against the Persians and had probably been sent on a scouting mission to determine whether the escape route to the west was clear. His news was greeted with dismay in the Greek camp, but the commanders resolved to sail out at dawn and take the Persians on in the narrows between Salamis and the mainland, hoping that the superior numbers of the enemy would count for less in such confined spaces.

In eager anticipation of a magnificent victory, King Xerxes positioned himself opposite Salamis with a good view of the small island of Psyttaleia, where a detachment of Persian troops had been landed during the night. But instead of witnessing his fleet's final triumph over the Greeks, Xerxes saw a naval disaster unfold before his very eyes. The various ethnic contingents of the Persian fleet were lined up several rows deep across the narrow channel with the Phoenicians on the right wing, nearest to Xerxes's position, and the Ionians on the left, nearest to Salamis. As they moved further into the channel their ships became so compacted and confused that they found it impossible to keep in formation. The crews were tired and to make matters worse a strong swell developed, making it even harder for the ships to make headway. Themistocles had anticipated this and seems to have persuaded the other Greek commanders to delay engaging the Persians until they were clearly in disorder. With the Athenian ships leading, the Greeks rowed out from the shore and turned towards the enemy. On a given signal their fresh crews surged forward and broke through the Persian lines to ram individual ships as they struggled to maneuver.

The Persians would have been expecting the Greeks to flee before their superior force, according to the plan worked out the previous day. But, like all ancient battles, once the action had started it was impossible to keep to a specific plan, and the captains of the individual ships were forced to make decisions on the spot. The main decision made by many of Xerxes's captains was to turn away from the attacking Greeks, causing confusion as they encountered more of their own ships trying to advance. In the resulting chaos the Greek captains urged on their much fresher crews and pressed the attack with great success.

It is impossible to describe the full course of the in detail. Our main source, the writer Herodotus, offers only a series of anecdotes about various groups of combatants. It was claimed that 70 Corinthian ships under Adeimantos and fled towards the Bay of Eleusis. It is likely that this supposed cowardly northward retreat which Herodotus presents as an Athenian slander against the Corinthians, may have been a deliberate move to engage the Egyptian squadron and prevent it from attacking the Greek rear. The Corinthians maintained that their ships did not encounter the Egyptians but returned to the battle and acquitted themselves as well as any of the Greeks. One of the most colorful anecdotes concerns Artemisia, the ruler of Herodotus's home city Alicarnassus, which was subject to the Persians. She was in command of her own ship and in the front line of the Persian fleet. When an Athenian trireme bore down on her she tried to escape, but found her path blocked by other Persian ships. In desperation she ordered her helmsman to ram one of them, which sank with the loss of all its crew. The pursuing Athenian captain assumed that Artemisia's ship was on his side and changed course towards another Persian vessel. Xerxes and his advisors saw the incident and recognized Artemisia's ship by its ensign, but their belief that she had sunk a Greek trireme then earned her the king's admiration. Xerxes is also said to have remarked at this point, 'My men have acted like women and my women like men.'

Another story concerns the Persian soldiers on the island of Psyttaleia. They were placed there in anticipation of the bulk of the Greek fleet being driven north and westwards away from the island. Instead they were isolated from their own ships and left vulnerable to attack from the nearby shores of Salamis. Right before Xerxes's eyes his elite troops, including three of his own nephews, were slaughtered by the Athenians.

Along the coast of Salamis, other Persians who managed to get ashore from their foundering ships were killed or captured. Towards the end of the day the Persian fleet retreated in confusion to the Bay of Phaleron, having lost more than 200 ships and having failed in its objective of forcing the Greeks away from Salamis. The Greeks had lost only about 40 ships and sent the enemy back to their anchorage in disarray.

Xerxes took the remains of his fleet and much of his army back to Anatolia, leaving his general Mardonius with a substantial army in central Greece. The following year a Greek army led by the Spartan king Pausanias defeated them at Plataea, north of Athens, effectively freeing mainland Greece from the threat of Persian domination. Themistocles was honored by the Spartans for his part in the victory, but his own countrymen seem to have turned against him, eventually forcing him to take refuge with the Persians. Xerxes's son Artaxerxes I made him governor of Magnesia on the Maeander River, where he died around 459 BC.

• 390 ships

• Commanded by Eurybiades (Spartan), Themistocles (Athenian), Adeimantos (Corinthian)

• 40 ships lost