Hoplites (HOP-lytes) (Ancient Greek: ὁπλίτης) were citizen-soldiers of Ancient Greek city-states who were primarily armed with spears and shields. Hoplite soldiers utilized the phalanx formation to be effective in war with fewer soldiers. … In the 8th or 7th century BC, Greek armies adopted the phalanx formation.
Sparta was a militaristic society. In Sparta practically every man was a member of the Spartan military. Taken from their parents at age seven to undergo the agoge (an intense military academy of sorts), they would continue to live in military barracks until age thirty.