Spartan army in the context of "Lycurgus of Sparta"

Spartan hegemony was the period of dominance by Sparta in Greek affairs from 404 to 371 BC. Even before this period the polis of Sparta was the greatest military land power of classical Greek antiquity and governed, dominated or influenced the entire Peloponnese. The defeat of the Athenians and the Delian League in the Peloponnesian War in 431–404 BC resulted in a short-lived Spartan dominance of the southern Greek world from 404 to 371 BC. Due to their mistrust of others, Spartans discouraged the creation of records about their internal affairs. The only histories of Sparta are from the writings of Xenophon, Thucydides, Herodotus and Plutarch, none of whom were Spartans. Plutarch was writing several centuries after the period of Spartan hegemony had ceased. This creates difficulties in understanding the Spartan political system, which was distinct from any other Greek polis.

The Theban–Spartan War of 378–362 BC was a series of military conflicts fought between Sparta and Thebes for hegemony over Greece. In 378 BC, led by General Epaminondas, Thebes revolted against its Spartan garrison and successfully repelled Spartan offensives. A clever tactician, Epaminondas crushed the hitherto invincible Spartan army at Leuctra in 371 BC, therefore ending Sparta's hegemony and starting Thebes' own hegemony over Greece. After Leuctra, the war continued in the Peloponnese, where Sparta was fighting for survival. In 362 BC, the Battle of Mantinea was a new victory for Thebes, but Epaminondas was also killed. The conflict ended soon after with a treaty of general peace signed by all the belligerents, except Sparta, which was by now isolated and permanently weakened.

The Peloponnesian War (Ancient Greek: Πόλεμος τῶν Πελοποννησίων, romanised: Pólemos tō̃n Peloponnēsíōn), was fought in the Eastern Mediterranean between the Athenian-led Delian League and the Spartan-led Peloponnesian League from 431 to 404 BC for hegemony over Ancient Greece. Initially inconclusive, the intervention of the Persian Empire in support of Sparta in 413 BC allowed the Spartan coalition to decisively defeat Athens, beginning a period of Spartan hegemony over Greece.

The war consists of four related conflicts which have traditionally been combined into one. The opening phase, called the Ten Years' War or the Archidamian War, began in 431 BC when the Spartan king Archidamus II invaded Attica with his army. After successive Spartan invasions of Attica and Athenian raiding of the Peloponnese, Athens gained the upper hand at Sphacteria in 425 BC, but lost it after a defeat by Thebes at Delium in 424 BC. With both city-states exhausted from years of fighting, the Peace of Nicias was signed in 421 BC. The second phase, the Argive War, was fought between 419 and 416 BC. It was a proxy war that pitted Sparta against its Peloponnesian rivals, led by Argos and supported by Athens. The Argive alliance was defeated at the battle of Mantinea of 418 BC, restoring Spartan hegemony over the Peloponnese. The third phase, the Sicilian Expedition, was an attempt by Athens to conquer the Spartan-allied Syracuse. Fought between 415 and 413 BC, the expedition ended in defeat for Athens and the destruction of most of its navy.