Ionia and the Ionian rebellion: 545-494 BC

When the Persians annexe Ionia in about 545, acquiring a foothold on the Aegean, the strongest city state in mainland Greece is Sparta. None of the Greek states risk an armed excursion in defence of the Ionians, but the Spartans do send a message to the Persian emperor, Cyrus, warning him to keep away from Greece. His reply, as reported, suggests genuine bewilderment. 'Who are the Spartans?', he asks.

Far from keeping away, an expedition of 514 approaches alarmingly close to Greece from the north, conquering Thrace and Macedonia to bring the northern coast of the Aegean under Persian control. But it is on the coast of Anatolia that the crisis intensifies.

In 499 BC the cities of Ionia rebel against their Persian satrap. They are supported to a limited extent by Athens. The rebellion continues fitfully until finally put down in 493. But this region is now established as an area of friction between Persia and Greece. Geographically Ionia seems a natural extension of Persia's great land empire. But culturally the Ionians are linked to all the other Greek-speaking peoples round the Aegean Sea.

Athens becomes the main target of the Persian emperor's hostility - partly because of her support for the Ionian rebels, but also because the tyrant Hippias, expelled from Athens, is at the Persian court offering treacherous encouragement. In 490 Darius launches his attack.

A Persian fleet sails along the southern coast of Anatolia. According to Herodotus, it numbers 600 ships. The horses of the famous Persian cavalry are in transport vessels; the troops are carried in Triremes.

From Ionia this armada sets a course straight across the Aegean, pausing only at Naxos and other islands to take hostages and press recruits into the army. The destination is Marathon, a plain to the north of Athens on which the cavalry will have room to manoeuvre. The army lands on the island of Euboea, conquers the small city of Eretria, makes the short crossing to the mainland at Marathon, and waits.

Marathon: 490 BC

In Athens the decision is taken to send an army to confront the Persians, rather than concentrate on defence of the city. A runner, whom Herodotus names as Pheidippides, is sent to seek help from Sparta. He completes the journey of about 150 miles (240 km) in two days. The Spartans agree to cooperate. But a religious ceremony prevents them from setting off until the next full moon, in six days' time.

At Marathon 10,000 Greek Hoplites confront perhaps 25,000 Persians. The Persians wait for the Greeks to attack across the plain, exposing themselves to the cavalry. The Greeks creep forward, night after night, with a ruse to frustrate the Persian horsemen.

They fell trees to create a barricade against the cavalry, and they move them gradually forward under cover of darkness. The plain has been considerably reduced in this way, when word comes one night that the Persian cavalry has moved temporarily elsewhere (the reason is unknown).

At dawn the Greek Hoplites charge in an extended line across the open ground. Their bronze armour and long spears prove too much for the lightly armed Persian infantry. Even so the Persian advantage in numbers means that the battle is hard fought, making Herodotus' account of the casualties (192 Athenian dead to 6400 Persians) somewhat hard to believe.

The Persian survivors are rescued from the beaches by the fleet, which then moves south to threaten Athens. The Athenian army marches rapidly home to defend the city, and the Persians decide against an assault. They withdraw across the Aegean.

A day or two after the event, 2000 Spartans arrive. They visit the battlefield as admiring tourists, to inspect the Persian dead. The fallen Athenians are buried beneath a great memorial mound (even today it stands 9 metres high). The survivors are acclaimed as heroes.Hoplites, the great tragedian, fought that day. He will have much in his life to be proud of. But nothing, he says, can compare with being a veteran of Marathon.

Themistocles and the Athenian fleet: 490-480 BC

Nobody doubts that the Persians will be back, but the death of Darius in 486 extends the lull before the storm. Three years later a rich new vein of silver is discovered in the mining district of Laureion, which is owned and run by the Athenian state.

Themistocles persuades his fellow citizens to apply their windfall to a collective cause - the building of a navy stronger than any other in Greece. By 480 there are 200 Triremes in the Athenian fleet.

Thermopylae: 480 BC

A vast Persian force led by Xerxes I, the son of Darius, is making its way along the northern coast of the Aegean. The troops are described in mesmerizing detail by Herodotus, writing only half a century later. He lists 1,700,000 soldiers (counted by a novel form of roll call), including 80,000 cavalry. They are accompanied by a fleet of 1207 Triremes, each with 200 men on board. Adding in subsidiary troops, Herodotus arrives at a grand total of 5,283,320 - not including eunuchs and female cooks.

These wildly improbable figures suggest the scale of the renewed threat as perceived in Greece. The only difference this time is that such a juggernaut moves slowly. There is time to plan.

At a central point of mainland Greece, the Isthmus of Corinth, thirty-one city-states meet - in the autumn of 481 and again in the spring of 480 - to devise a strategy. It is agreed that all will combine their resources, both military and naval, in a common force under the command of Sparta.

The immediate question is where to make a stand against the advancing Persians. The chosen site is Thermopylae, a long narrow valley through which any army must pass if moving down the coast towards Athens.

Leonidas, one of the two Spartan kings, is in command of the Greek army when the confrontation comes. His Spartan contingent is as yet only an advance guard of 300 men. He stations them under his immediate command at the narrowest part of the pass.

The glittering Persian army has at its head the emperor himself, Xerxes, son of Darius. On two successive days he orders his best troops into the narrow defile. But as at Marathon, ten years earlier, the Persians suffer heavy losses from the longer spears of the Greek Hoplites. The situation appears to be an impasse, almost literally - until it is resolved by treachery.

In the hope of a large reward a Greek (a certain Ephialtes, named by Herodotus to ensure his eternal infamy) informs Xerxes that a hidden path through oak woods on the nearby hills will bring troops, unseen, to the other side of the pass. A Persian contingent takes that route during the night.

Before dawn, spies bring Leonidas news of the imminent danger. He orders the main body of the army to retreat southwards. Then he prepares, with his 300 Spartan Hoplites and a few others, to face an onslaught from both ends of the pass.

All the Spartans die, selling their lives at a high price - Herodotus writes that the terrified enemy soldiers had to be whipped by their commanders into confronting these Greeks. Their fate becomes the enduring monument to Spartan discipline and valour, captured in a famous epitaph inscribed on a column in the pass: 'Stranger, go tell the Spartans that we lie here - obedient to their laws.'

Now it is the Athenians who are in the front line against the victorious invaders. As the Persian army moves south towards Attica, the debate in Athens is whether to defend the city or make a strategic withdrawal.

Salamis: 480 BC

Themistocles, who has already persuaded his fellow citizen to invest in a navy, urges withdrawal. According to a story told by Herodotus, he makes good use of the oracle at Delphi which has told them to put their trust in a 'wooden wall'. What the oracle clearly has in mind, he argues, is a ship.

His advice is accepted. Athens is evacuated, apart from a few stalwarts who interpret the 'wooden wall' differently; they retreat to the sacred precinct of the acropolis and build round it a wooden palisade. The rest of the inhabitants are taken by ship across the narrow strait separating Athens from the island of Salamis.

Reaching Athens, the Persians fire blazing arrows into the wooden barricade. Then, with some difficulty, they assault the steep acropolis. After slaughtering those sheltering in the temple, they seize the treasures and demolish the buildings. Athens, so recently given a new grandeur in the reign of Peisistratus, is reduced to rubble. But the destruction will make possible the Rebuilding of athens and an even more glorious city.

Meanwhile the Greek fleet is gathered in the narrow stretch of water between Salamis and the mainland. Themistocles persuades his allies to make a stand here, prevailing over those Peloponnesian states who would prefer to abandon Attica and draw the line at the more defensible Isthmus of Corinth.

The Greek fleet is smaller than the Persian. It numbers only 380 Triremes (of which about half are Athenian), and the Greek ships are slower. Themistocles argues that these disadvantages will be irrelevant in a restricted space, where Greek fighting skills can tip the balance (as in the narrow pass at Thermopylae).

His plan depends on the Persian fleet being enticed into the strait at the eastern end of the island of Salamis. Prompted by some deliberately misleading diplomacy, the Persians fall into the trap. As the Greek Triremes begin to ram and sink them, panic spreads among the constricted Persian ships - making them ever more vulnerable. The Greek victory is overwhelming.

Plataea and Mykale: 479 BC

The Persians are still occupying Attica, and the Athenians cannot hope to dislodge them without Spartan assistance. This is provided in 479, when a large Greek army marches north from the Peloponnese. It meets the Persians at Plataea, where the Spartan commander, Pausanias, wins a victory against considerable odds.

Meanwhile the Persian navy has retreated across the Aegean. The Greek fleet confronts them again at Mykale, where the Persians make discretion the better part of valour. They abandon their ships rather than face the Greek triremes, but they are then defeated by the Greeks in a battle on shore. The westward expansion by Xerxes has been brought to a conclusive end.

The Greek colonies in Asia Minor remain under Persian control, and the attempt to recover them will continue for many years. An early success is the liberation of Byzantium, at the mouth of the Black Sea, in 478.

Sparta is not interested in naval expeditions against the Persians in Asia, so the leadership of the Greek forces passes to Athens and the Delian league. By 448 BC the Persians have been cleared from all the Greek territories. There is some evidence that in that year a formal agreement is reached - known as the Peace of Kallias - which excludes the Persian fleet from the Aegean and guarantees the independence of the Greek states of Asia Minor.