The preparations and invasion of Xerxes (480 BC), the Hellenic League, the battles of Thermopylae, Artemisium, and Salamis, and the strategic role of Themistocles' naval policy

What this dot point is asking

NESA expects you to describe the second Persian invasion of Greece in 480 BC under Xerxes: the scale of Persian preparations, the formation of the Hellenic League, the linked battles of Thermopylae and Artemisium, the evacuation of Athens, and the Greek naval victory at Salamis.

The answer

Persian preparations (483 to 481 BC)

Xerxes, who succeeded Darius in 486 BC, spent four years preparing the invasion.

The army. A combined-arms force drawn from across the empire. Herodotus (7.184 to 187) gives 1,700,000 infantry; modern historians estimate around 200,000 combatants and 80,000 horses, plus camp followers and a fleet of around 1,200 ships. The army was the largest the ancient world had ever seen.

The fleet. Phoenician, Cypriot, Egyptian, Cilician, and Ionian Greek squadrons. The Persian-controlled Greek cities of Ionia were obliged to provide ships and crews.

The Athos canal. To avoid the disaster of 492 BC, Xerxes had a canal dug through the isthmus at the foot of Mount Athos. It was three years in construction; archaeological remains confirm the route.

The Hellespont bridges. Two pontoon bridges of 674 ships moored together carried the army from Asia to Europe at Abydos. The first set, destroyed by storm, was rebuilt; Xerxes had the sea flogged 300 times for its insolence (Herodotus 7.35).

Supply. Magazines were stockpiled along the route through Thrace and Macedonia.

The Greek response: the Hellenic League

The Hellenic League formed at a congress at the Isthmus of Corinth in autumn 481 BC. Thirty-one states joined; many others medised (submitted to Persia) including Thebes (after Thermopylae), Thessaly, and most of central and northern Greece.

Leadership. Sparta took overall command by land and sea. The Athenians ceded naval leadership to the Spartan Eurybiades to keep the alliance together (Herodotus 8.2 to 3).

Strategy. The League initially considered defending at the Vale of Tempe in Thessaly (a 10,000-strong force was sent and withdrawn) before settling on the linked positions at Thermopylae and Artemisium.

Themistocles's naval policy

In 483/2 BC a new vein of silver was struck at Laurion in southern Attica. The annual revenue was around 100 talents. Themistocles, then in his political prime, persuaded the Athenian Assembly to spend the windfall on a fleet of 200 triremes rather than distribute it. He framed the proposal as preparation for war with Aegina (Herodotus 7.144); the real target was Persia. By 480 BC Athens had the largest fleet in Greece.

Thermopylae (mid August 480 BC)

The Hellenic League force of around 7,000 hoplites under the Spartan king Leonidas I (300 Spartiates plus contingents) held the narrow coastal pass at Thermopylae for three days against the Persian advance.

Days 1 and 2. Frontal Persian assaults including the elite Immortals were repulsed by hoplites in close formation in the narrow pass.

The Anopaea path. A local, Ephialtes of Trachis, betrayed an alternative mountain path to Xerxes. The 1,000 Phocian guards on the path were dislodged by Persian troops at dawn on the third day.

Day 3. Leonidas dismissed most of his force, holding the position with the 300 Spartiates, 700 Thespians (voluntarily), and 400 Thebans. All were killed. The Persians broke through. Simonides's epitaph for the Spartan dead survives: "Go, tell the Spartans, you who pass by, that here, obedient to their laws, we lie."

Artemisium (mid August 480 BC)

Simultaneous with Thermopylae the Greek fleet of 271 (later 380) triremes engaged the Persian fleet off Cape Artemisium in northern Euboea.

The storm. A three-day storm wrecked perhaps 400 Persian ships off the south-east coast of Magnesia (Herodotus 7.188 to 192). The Greek fleet, sheltered on the western coast of Euboea, was unaffected.

Three days of fighting. Inconclusive; both sides took losses. The Greeks experimented with trireme tactics they would refine at Salamis.

Withdrawal. After news of Thermopylae the Greek fleet withdrew to Salamis. Themistocles allegedly left messages at the watering places urging the Ionian crews to defect (Herodotus 8.22).

The evacuation of Attica

After Thermopylae the Persian army marched south through Boeotia (Thebes medising) and into Attica. The Athenians evacuated the population to Troezen, Aegina, and Salamis. The Themistocles Decree (preserved on the Troezen inscription, a third-century BC copy of a 480 BC decree) records the mobilisation. The Acropolis was held briefly by old men and the temple treasurers, then stormed and burned. The "Persian destruction debris" deposited on the Acropolis is the archaeological marker.

The Battle of Salamis (around 29 September 480 BC)

The Greek fleet, around 380 triremes (180 Athenian, around 30 Aeginetan, 16 Spartan, plus others) under Spartan command (Eurybiades) but tactical leadership (Themistocles), gathered in the narrow strait between the island of Salamis and the Attic mainland.

The council. The Peloponnesian commanders argued for withdrawing to the Isthmus to defend the Peloponnese. Themistocles argued for Salamis: the narrows favoured fewer ships; abandoning Athens entirely would shatter the alliance.

The Sicinnus stratagem. Themistocles sent his slave Sicinnus to Xerxes with the message that the Greek fleet would flee that night and that Xerxes should block the exits to catch them (Herodotus 8.75). Xerxes ordered his fleet (perhaps 700 ships) to block both ends of the strait. Greek withdrawal was now impossible.

Aristides's news. Aristides "the Just," recalled from ostracism, brought confirmation that the Persians had blocked the channel.

The battle. At dawn the Persian fleet entered the narrows. The crowded Persian fleet could not deploy its numerical advantage. Greek triremes, heavier and with better-trained Athenian crews, rammed and disabled Persian ships in succession. Xerxes watched from a throne on the slope of Mount Aigaleos. Queen Artemisia of Halicarnassus distinguished herself on the Persian side. The Persian fleet was broken; perhaps 200 to 300 ships were lost to 40 Greek.

Aeschylus, Persians. The playwright fought at Salamis and recreated the battle in the Persians, performed in 472 BC. The play is the earliest surviving Greek tragedy and the only one on a contemporary subject.

Xerxes's withdrawal

After Salamis Xerxes himself withdrew to Asia with most of the army, leaving Mardonius and around 50,000 picked troops to winter in Thessaly and continue the campaign in 479 BC. Themistocles sent a second (probably false) message warning Xerxes that the Greeks would destroy the Hellespont bridges (Herodotus 8.110), urging speed.

The sources

Herodotus, Histories 7 to 8. The major source. Probably written within a generation of the events, drawing on Greek and (limited) Persian testimony.

Aeschylus, Persians (472 BC). The earliest surviving Greek tragedy. A direct eyewitness account of Salamis from the Greek side.

Plutarch, Lives. Themistocles and Aristides include details from lost Hellenistic authors.

The Troezen inscription (Themistocles Decree). A third-century BC copy of a 480 BC Athenian decree on the evacuation. Discovered in 1959, its authenticity is debated.

Archaeology. The "Persian debris layer" on the Athenian Acropolis; the polyandreion at Thermopylae; the trophies at Salamis; the Serpent Column at Delphi (a Greek dedication after Plataea listing the 31 League states).

How to read a source on this topic

Section IV sources on Xerxes's invasion typically include extracts from Herodotus 7 to 8, Aeschylus's Persians, or the Troezen inscription. Three reading habits.

First, distinguish the eyewitness from the literary frame. Aeschylus was there; Herodotus was not. Both have rhetorical purposes.

Second, watch the numbers. Herodotus's Persian totals (1,700,000 infantry; 1,200 ships) are impossible. The order of magnitude is around 200,000 combatants and perhaps 1,000 ships before storm losses.

Third, integrate the linked battles. Thermopylae and Artemisium were one defensive line, not two separate events. Salamis is the consequence of their loss.

Common exam traps

Treating Thermopylae as a Greek defeat alone. It was lost tactically, but it bought time, sustained morale, and made Leonidas the iconic figure of Greek resistance.

Ignoring Artemisium. The naval engagements are essential context for Salamis.

Crediting Themistocles alone. The fleet was a public Athenian achievement; Eurybiades commanded; Aristides delivered intelligence.

Forgetting the storm. The storm off Magnesia destroyed perhaps a quarter of the Persian fleet. Greek skill was decisive but Persia also suffered great natural losses.

In one sentence

Xerxes's invasion of Greece in 480 BC, prepared with the Athos canal, the Hellespont bridges, and an army and fleet larger than any seen before, was checked by the Hellenic League at the linked engagements of Thermopylae and Artemisium (mid August 480 BC, with the death of Leonidas and the 300 Spartans), reached Athens and burned the Acropolis after the evacuation organised under the Themistocles Decree, and was decisively defeated at Salamis (late September 480 BC) where Themistocles's stratagem to commit the Persian fleet to the narrows produced a naval victory recreated by Aeschylus in the Persians of 472 BC.