The ancient Greek city-state known for its military prowess is Sparta. Renowned for its disciplined and formidable army, Sparta emphasized a unique education system called agoge that trained male citizens for military service from a young age. Spartan society revolved around martial excellence, austerity, and communal living, which fostered a culture devoted to war and discipline. The Spartans played a crucial role in various key battles, including the famous stand at Thermopylae against the Persian army. Their militaristic lifestyle and strategies significantly shaped Greek warfare and influenced subsequent military practices in history.