Education played a significant role in ancient Greek life since the founding of the poleis till the Hellenistic and Roman period.
With origins lying on the homeric and the aristocratic tradition, education was vastly "democratized" in the 5th century BC, influenced by the Sophists, Plato and Isocrates. In the Hellenistic period, education in a gymnasium was considered an inexctricable prerequisite for participation in the Greek culture.
In Athens, adolescents were required to pass a bi-annual training in order to become citizens called ephebeia. After the battle of Chaeronia, when a major reform was undertook by Lycurgus, ephebeia became compulsory for all Athenian to-be-citizens 1 . There is no accordance among historians as to if there were any timocratic criteria for acceptance in the body of the ephebes in any of the phases of the institution. Besides Lycurgus' evidence 1, there is no such information concerning the time c. 325 in the relevant chapter of Constitution of the Athenians2
Sparta
The most known exception of the common educational system is that of Sparta, a polis that maintained till the Roman age the harsh military agoge training system for boys and girls in the same form as it was created in the 6th century BC.