Sparta
At birth spartan boys (and girls) were examined and any boy who was not physicly strong and healthy was left in the woods to die. Boys who survived were raised and at the age of 7 put into public 'schools' were they learned gymnastics, sports, fighting and participated in other forms of physical activities. They were not allow to wear shoes, use beds, ate meager food and had only a simple cloak, even during winter.
At age 20, the Spartan citizen began his membership in one of the syssitia (dining messes or clubs), composed of about fifteen members each, of which every citizen was required to be a member. Here each group learned how to bond and rely on one another. The Spartans were not eligible for election for public office until the age of 30. Only native Spartans were considered full citizens and were obliged to undergo the training as prescribed by law, as well as participate in and contribute financially to one of the syssitia.
Sparta is thought to be the first city to practice athletic nudity, and some scholars claim that it was also the first to formalize Pederasty. According to these sources, the Spartans believed that the love of an older, accomplished aristocrat for an adolescent was essential to his formation as a free citizen. The Agoge was, they claim, founded on pedastric relationships required of each citizen, with the lover responsible for the boy's training.
Spartan men remained in the active reserve until age 60. Men were encouraged to marry at age 20 but could not live with their families until they left their active military service at age 30. They called themselves "homoioi" (equals), pointing to their common lifestyle and the discipline of the phalanx, which demanded that no soldier be superior to his comrades. Insofar as hoplite warfare could be perfected, the Spartans did so.
References
Wikipedia contributors, 'Sparta', Wikipedia, The Free Encyclopedia, 2 March 2025, 11:48 UTC, <https://en.wikipedia.org/w/index.php?title=Sparta&oldid=1278427463> [accessed 2 March 2025]