Key Facts
- Duration
- 27 years (431–404 BC)
- Total casualties (est.)
- ~100,000
- Decisive battle
- Aegospotami, 405 BC — Spartan victory
- Major phases
- 4 (Archidamian War, Argive War, Sicilian Expedition, Decelean War)
- Persian role
- Financed Spartan fleet from 413 BC onward
Strategic Narrative Overview
The war unfolded in four phases. The Archidamian War (431–421 BC) saw Spartan land invasions countered by Athenian naval raids, ending inconclusively in the Peace of Nicias. A proxy Argive War (419–416 BC) restored Spartan dominance in the Peloponnese. Athens then launched the disastrous Sicilian Expedition (415–413 BC), losing most of its fleet at Syracuse. Persia then bankrolled a Spartan navy; Lysander's victory at Aegospotami in 405 BC shattered Athens's remaining naval power.
01 / The Origins
By the mid-fifth century BC, Athens had built a powerful maritime empire through the Delian League, generating deep resentment among Sparta and its Peloponnesian allies. Competition for hegemony over the Greek world, tensions over tribute-paying states, and Corinthian pressure on Sparta converged to make conflict nearly inevitable. In 431 BC, Spartan king Archidamus II invaded Attica, opening a war between two rival alliance systems with incompatible political ideologies—Athenian democracy versus Spartan-backed oligarchy.
03 / The Outcome
Athens surrendered in 404 BC and the Delian League was dissolved. Sparta imposed oligarchic governments across former Athenian ally states, most notoriously the Thirty Tyrants in Athens. Spartan hegemony proved brief: Athens recovered independence within a decade during the Corinthian War. The war left widespread poverty across Greece, ended Athens's golden age, and contributed to conditions that enabled eventual Macedonian and foreign domination of the region.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Pericles, Alcibiades, Nicias.
Side B
2 belligerents
Archidamus II, Lysander.
Kinetic Engagement Axis
Scroll horizontally to view full axis. Events plotted relatively.