Quick questions on Xerxes' invasion of Greece (480 BC): HSC Ancient History

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

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.

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.

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.

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

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 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.

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.

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

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.

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

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.

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).

Magazines were stockpiled along the route through Thrace and Macedonia.

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).