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Why did Xerxes' vast invasion of Greece in 480 BC end in defeat?

The accession of Xerxes and his great invasion of Greece in 480 BC: the bridging of the Hellespont and the canal at Athos, the battles of Thermopylae and Artemisium, Salamis and Plataea, and the reasons for the Persian failure, studied through Herodotus Book 7.

An OCR GCSE Ancient History answer on the invasion of Greece by Xerxes in 480 BC, covering his preparations and the bridging of the Hellespont, Thermopylae and Artemisium, the decisive sea battle of Salamis and the land battle of Plataea, and why the great Persian invasion failed, studied through Herodotus Book 7.

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Xerxes (reigned 486 to 465 BC), son of Darius, launched a huge invasion of Greece in 480 BC to avenge Marathon and complete his father's plan. He prepared on a vast scale, bridging the Hellespont with boats and cutting a canal through the Athos peninsula to avoid the storms that had wrecked an earlier fleet. A Greek alliance led by Sparta and Athens resisted. At Thermopylae the Spartan king Leonidas and his men held a narrow pass for days before being outflanked and killed, while the fleets fought an indecisive battle at Artemisium. The Persians then took and burned Athens. But at the sea battle of Salamis, the Athenian leader Themistocles lured the huge Persian fleet into narrow straits where its numbers were a handicap, and the Greeks destroyed it. Xerxes returned home, leaving his general Mardonius, who was defeated and killed at the land battle of Plataea in 479 BC. The invasion failed through a combination of Persian misjudgements (fighting at Salamis, the over-long supply line), Greek strengths (Themistocles's strategy, the terrain, hoplite quality and unity at the decisive moments), and Herodotus's framing of the whole as the punishment of a king's overreaching pride.

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What this dot point is asking

The period study climaxes with the invasion of Greece by Xerxes in 480 BC, the largest expedition the ancient world had seen, and its dramatic failure. You need the narrative (the preparations, Thermopylae, Salamis, Plataea) and you must be able to explain why so vast an invasion failed. The main source is Herodotus Book 7 (and Books 8 to 9), who tells the story as a moral drama of Persian hubris punished, so you must use his vivid account critically.

The answer

Xerxes and the great preparations

Herodotus presents these feats as evidence of both Persian power and Xerxes's hubris, especially the story that Xerxes had the sea whipped when a storm broke his first bridge.

Thermopylae and Artemisium

Salamis: the decisive battle

Plataea and the end of the invasion

Why the invasion failed

Examples in context

Building a 20-mark essay on why Xerxes' invasion failed

step 1 Set up the two sides

Plan one column for Persian mistakes (Salamis, supply line, Xerxes leaving) and one for Greek strengths (Themistocles, terrain, hoplites, unity).

step 2 Argue the Persian errors

Explain that fighting at Salamis in narrow straits wasted the Persian numerical advantage, and that the long sea supply line and Xerxes's early departure weakened the campaign.

step 3 Argue the Greek strengths

Explain Themistocles's strategy at Salamis, the use of terrain at Thermopylae and Plataea, hoplite quality, and Greek unity at the crucial battles.

step 4 Judge and write for SPaG

Conclude, for example, that Persian decisions at Salamis were decisive but only because the Greeks exploited them. Because the printed tariff includes 5 SPaG marks, write in accurate, well-organised prose.

A model answer balances Persian mistakes against Greek strengths and reaches a judgement, while remembering that Herodotus frames the failure as punished pride.

Try this

Q1. Name the decisive sea battle of 480 BC and the Athenian leader who shaped the Greek strategy. [Knowledge recall]

Cue. The Battle of Salamis; the Athenian leader was Themistocles.

Q2. Explain why fighting at Salamis was a Persian mistake. [Short explanation]

Cue. The narrow straits off Salamis meant the much larger Persian fleet could not use its numbers and became crowded and disordered, so the Greeks could fight it on more equal terms and won, destroying the fleet that supplied Xerxes's army.

Exam-style practice questions

Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

OCR J198/01 20198 marksStudy Sources A and B (both from Herodotus Book 7 on Xerxes' preparations). How far do these sources agree about the scale of Xerxes' invasion? [8-mark source-comparison question]

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A Section A source-comparison question (AO3) on two passages from a prescribed author.

Agreement. Both stress the enormous scale of the expedition: huge numbers of men and ships drawn from across the empire, and great engineering feats such as the bridging of the Hellespont and the canal cut through the Athos peninsula.

Difference. One passage may emphasise the discipline and grandeur of the host, the other the hubris of the king (the whipping of the sea, the vast but unwieldy army), reflecting Herodotus's moralising frame.

Judgement. Conclude that they agree on the scale but may differ in tone, and note that Herodotus exaggerates numbers and frames the invasion as overreaching pride, so the sources need testing.

OCR J198/01 202120 marks'Xerxes' invasion of Greece failed mainly because of poor Persian decisions.' How far do you agree? [shown at the 20-mark essay style; the printed tariff is 20 marks including 5 for SPaG]

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A Section A extended essay (AO1 and AO2). The printed tariff is 20 marks, of which 5 are for spelling, punctuation and grammar, so the historical content is marked out of 15.

For the statement. Persian errors: fighting at sea in the narrow straits of Salamis (where numbers could not be used), the over-long supply line, and Xerxes leaving before the campaign was finished.

Other factors. Greek strengths: the leadership of Themistocles, the defensive terrain, hoplite quality at Plataea, and Greek unity at the crucial moments.

Judgement. Weigh Persian mistakes against Greek strengths and reach a supported conclusion, for example that Persian decisions at Salamis were decisive but only because the Greeks exploited them. Write the SPaG-credited essay in accurate, well-organised prose.

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Sources & how we know this

OCR GCSE (9-1) Ancient History J198 specification — OCR (2017)
Herodotus, Histories, Books 7 to 9 — Perseus Digital Library