Education in A Nutshell: From the minor's privilege
to a compulsory education
It was chalk and cheese with Sparta's model, which had been designed to train fiercely loyal, gallant and physically perfectly healthy warriors. Upon turning seven, boys would have been moved out to live in either schools or barracks, wherein they were exposed to sports and combat and endurance training with iron disciplines. Albeit being elite combat troops, they were, for the most part, illiterate.
By the Middle, Middle Ages (circa the 1000s and 1250s), European schools, which chiefly thrived on religious principles, were to train clergies primarily. As their antecedents, the earliest universities, take the University of Paris (1160) as an example, were Catholic-based. Howbeit kept running; both state-owned and private institutions were also to serve religious purposes.
Given that at the very core of education (or any other political activity) was the ruling elites, the system itself is neither entirely negative nor extreme.
In addition to spreading the feudalism ideology, ancient Chinese education as well channelled citizens to harmonious social relationships, ritual customs and even music, which by all means centred the Confucian philosophy, a matter of history.
By the fourth century BC, Roman education had already made certain leaps forward. It paid more attention to fundamental socialization and early childhood education. Regular schools did demand low tuition fees and accepted both male and female students. They developed the very earliest form of a hierarchical school system close to today. Since the Catholic school system didn't purely revolve around a catechism, instead, it as well got students exposed to literature, arts, and other forms of knowledge.
2. From the minor's privilege to a compulsory education
We live in a world, wherein mandatory schooling has become a social norm, given that school had, for most of the parts of human history, been a privilege granted to the minority - the elites and rulers.
To put into perspective, the ancient Eastern education system was pretty much driven by classism. The theocratic Egyptian society got priests to represent the elite intellectual class with reliable power. Together with court officials, they oversaw the exclusive privileged youth education. Only scribes could enjoy the hieroglyph reading and writing privilege, and lest royal or noble, one would hardly ever be exposed to "noble" subjects: medicine, science or mathematics.
In a like manner, the ancient Mesopotamian and Indian education was as much limited to those of high social status.
After years of ever-evolving advancement, the school system, to a certain extent, has done away with wealth (both the privileged and unprivileged), gender (both male and female) and political and religious status classism.
For the most part, ancient Greek education was private. The IV-century-BC Athens allowed anyone to open class and decide on what to be taught. Even down-and-out children could enjoy learning.
Insomuch as the Protestant Reformation (the 1400s) did abolish the holy European education.
As an antecedent of the Protestant Reformation, the Prussian Empire's compulsory education system (the Germany predecessor) popped up by the second half of the eighteenth century to button down the state's supreme education power. It was still driven by the inherent political-educational orientation to "create submissive soldiers and citizens". The second goal was to "nurture and uplift nationalism through the education control on the youth".
It was not until the 1830s that the system began adhering to more strict principles: graded classes, free primary education; trained and well-paid teachers (as other careers) from professional schools; state budgets on the school infrastructure construction and supervision to ensure the education quality. It was not to mention that the curriculum must have been nationalism-oriented, coevally combined with science and technological knowledge and secularly taught (apart from religion).
Adopted in America by Horace Mann by 1843, such a system has since become the K12 model, thereupon modelled on by many other countries, ending up the standardized international educational policy.