Final answer:
The downfall of Sparta occurred due to its transition to a naval power, reneging on promises to Persia, defeat by Thebes at the Battle of Leuctra, loss of its helot labor force, and the exhaustion of the Greek city-states after prolonged warfare.
Step-by-step explanation:
The downfall of Sparta can be traced through a series of key events starting post-Persian Wars to the end of the Peloponnesian War and its aftermath. Despite their initial dominance after the Peloponnesian War, several strategic errors and shifts in alliances contributed to Sparta's decline.
- Sparta's transition from a land-based power to a naval power during the Peloponnesian War to match Athens.
- The end of the war in 404 BCE where Sparta imposed oligarchies in Athenian territories but soon reneged on its promises to Persia.
- Persian funding of Greek resistance to Sparta, ultimately leading to the loss of the Ionian states.
- Sparta's former identity was compromised as it became a diplomatic player, and its hoplite-based social order weakened.
- The shock defeat by Thebes in 371 BCE at the Battle of Leuctra, which displayed Sparta's military vulnerability.
- The liberation of Messene by Thebes in 370 BCE, leading to the collapse of the Spartan helot system essential for its military.
- The eventual exhaustion of Greek city-states by 350 BCE after decades of warfare.
These points mark the transition of Sparta's place in Greek society from a leading military power to a state outpaced by its rivals and inner societal changes.