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Military conflict: Alexander the Great and Macedonian conquest (SACE Stage 2 Ancient Studies)

Syllabus dot point

“Analyse the causes, key campaigns and consequences of Alexander's conquest of the Persian Empire (336 to 323 BCE), and evaluate the reliability of the surviving sources written centuries later.”

7 min read

Quick answer

Between 336 and 323 BCE Alexander III of Macedon conquered the vast Persian Empire and reached India, building on the army and ambitions of his father Philip II. He defeated the Persians at Granicus (334 BCE), Issus (333 BCE) and decisively at Gaugamela (331 BCE), took Egypt and Babylon, and pushed east before his troops turned back at the Hyphasis. He died at Babylon in 323 BCE aged thirty-two, leaving an empire that fragmented among his generals. Our problem is that no contemporary narrative survives: the main sources were written three to five centuries later, using lost earlier accounts.

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  1. What this dot point is asking
  2. Causes: the inheritance from Philip
  3. The decisive campaigns
  4. The eastern campaigns and the limit of conquest
  5. Consequences
  6. Evaluating the sources
  7. Why this matters for your study
  8. Assessment-style questions

What this dot point is asking

You must explain how and why Alexander conquered so rapidly, narrate the decisive campaigns, assess the consequences, and evaluate sources that are unusually distant from the events.

Causes: the inheritance from Philip

Alexander's conquests were built on foundations laid by his father, Philip II of Macedon, who reformed the army with the long pike (sarissa) and the disciplined phalanx, integrated cavalry, and unified Greece under Macedonian leadership in the League of Corinth. Philip planned an invasion of Persia, framed as revenge for the earlier Persian invasions of Greece, but was assassinated in 336 BCE. Alexander inherited a battle-ready professional army and the campaign already prepared, and added his own relentless drive.

The decisive campaigns

Crossing into Asia in 334 BCE, Alexander won at the river Granicus, then defeated the Persian king Darius III himself at Issus in 333 BCE. Rather than pursuing Darius at once, he secured the eastern Mediterranean coast, taking the great fortress city of Tyre after a famous siege and entering Egypt, where he founded Alexandria. He then met and crushed Darius' main army at Gaugamela in 331 BCE, opening the Persian heartland and the capitals of Babylon, Susa and Persepolis, the last of which was burned.

Gaugamela broke the Persian Empire

At Gaugamela in 331 BCE, Alexander defeated a far larger Persian army on ground chosen by Darius, using disciplined infantry and a decisive cavalry charge aimed at the king. The victory shattered organised Persian resistance and effectively delivered the empire, since Darius soon fled and was murdered by his own officers.

The eastern campaigns and the limit of conquest

Alexander pressed on into Central Asia and India, defeating the Indian king Porus at the Hydaspes in 326 BCE. There his exhausted troops refused to march further east at the river Hyphasis, and he turned back. The return through the Gedrosian desert cost many lives. He died at Babylon in 323 BCE, his sudden death amid plans for further campaigns leaving no settled succession.

Hellenistic world

The Hellenistic world is the era after Alexander's death (from 323 BCE) in which Greek language, culture and rule spread across the former Persian Empire under Alexander's successor dynasties, blending Greek and eastern traditions in kingdoms such as Ptolemaic Egypt and the Seleucid realm.

Consequences

Alexander's empire did not survive him as a unit. His generals, the Diadochi, fought over the inheritance and carved out the great Hellenistic kingdoms. Yet the conquest spread Greek language, art and city-founding across the Near East for centuries, creating the Hellenistic world in which Greek culture mixed with Egyptian, Persian and Mesopotamian traditions, and through which much classical learning later reached Rome.

Evaluating the sources

The source problem is acute and central to any SACE study of Alexander. Eyewitnesses such as his officer Ptolemy and the engineer Aristobulus wrote accounts, but these are lost. Our surviving narratives, by Arrian, Plutarch, Diodorus, Curtius and Justin, were composed between roughly three and five centuries after Alexander, drawing on the lost earlier works. Arrian is usually rated most reliable because he followed Ptolemy and Aristobulus and wrote soberly, while others are more rhetorical or sensational. All wrote when Alexander had become a legend, so glorifying and moralising traditions shape every account.

Why this matters for your study

Alexander is a classic SACE military-conflict topic precisely because the brilliant narrative rests on such late evidence. Strong responses use accurate dates and battles while constantly noting that our sources are centuries removed and depend on lost originals, and they distinguish the more careful Arrian from the more colourful tradition.

Common mistake

Do not treat the late sources as if they were eyewitness reports. Repeating dramatic anecdotes from Plutarch or Curtius as established fact, without noting that they wrote centuries after the events and that the contemporary accounts are lost, shows exactly the lack of source criticism the course penalises.

Planning a 20 mark essay on Philip's contribution to Alexander's success

A SACE essay rewards a weighed argument about causation, not a campaign narrative.

Step 1: Define the question

Distinguish what Alexander inherited from what he added, and set criteria: army, strategy and leadership.

Step 2: Establish the inheritance

Show Philip's sarissa phalanx, integrated cavalry, the League of Corinth and the prepared invasion of Persia.

Step 3: Establish Alexander's contribution

Show his battlefield decisions at Issus and Gaugamela, his relentless pace and personal command.

Step 4: Weigh the factors

Decide whether the inheritance or Alexander's own genius was more decisive, treating one as foundation and the other as catalyst.

Step 5: Reach a judgement

Conclude that the inheritance was necessary but not sufficient, evaluating the reliability of the late sources.

Assessment-style questions

Questions on this dot point, each with a worked answer, written by ExamExplained. Ancient History has no written exam, so use them to check your understanding before your assessment tasks.

Practice15 marks
Source A is an extract from Arrian's account of Alexander's victory at Gaugamela. With reference to its origin, purpose and content, analyse the usefulness of this source for a historian investigating Alexander's conquest of Persia.
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A SACE source-analysis response wants origin, purpose and content tied to a judgement about usefulness, not a paraphrase of the passage.

Origin and purpose. Identify Arrian as a writer roughly four centuries after the events who followed the lost eyewitness accounts of Ptolemy and Aristobulus, aiming at a sober narrative.

Usefulness. Argue it is among our most reliable sources because of its careful basis, but it is still distant from the events, dependent on lost originals, and written when Alexander was a legend.

Make the analytical move that even the best surviving source is late and second-hand, and cross-check the more sober Arrian against the rhetorical tradition of Curtius and Plutarch.

Markers reward the origin-purpose-content link and a judgement on usefulness for the inquiry.

Practice20 marks
How far did Alexander's success depend on the army and plans he inherited from Philip II?
Show worked answer →

A 20 mark extended response needs a thesis weighing inheritance against Alexander's own contribution.

Thesis. Argue that Philip's reformed army and prepared campaign were essential foundations, but Alexander's leadership and drive turned them into conquest.

For inheritance. Show the sarissa phalanx, integrated cavalry, the League of Corinth and the planned invasion.

For Alexander. Show his battlefield decisions at Issus and Gaugamela, his relentless pace and his personal command.

Judgement. Conclude with a weighed verdict that the inheritance was necessary but not sufficient, evaluating the late sources.

Markers reward a structured argument and source criticism.

Practise this

Sources & how we know this

ExamExplained