The Spartans were a pacifistic society.
Sparta . Given its military pre-eminence , Sparta was recognized as the overall leader of the combined Greek forces during the Greco-Persian Wars . Between 431 and 404 BC , Sparta was the principal enemy of Athens during the Peloponnesian War , from which it emerged victorious , though at a great cost of lives lost . Sparta 's defeat by Thebes in the Battle of Leuctra in 371 BC ended Sparta 's prominent role in Greece . Spartiates underwent the rigorous agoge training and education regimen , and Spartan phalanges were widely considered to be among the best in battle .