Compulsory state education systems are generally a recent phenomena in terms of known human history. In the past, people usually educated their children in whatever manner they chose and the matter was no concern of the state.
In ‘The Republic’Plato popularised the concept of compulsory education in Western intellectual thought.  Plato may well have had in mind Sparta which took boys at age seven and segregated them in the Agoge system in which they lived communally in a ‘dog eat dog” world and studied physical and weapons training, and reading, writing, music and dancing until age 18. Girls may well have had a similar though less vicious system.
The Talmud (tractate Bava Bathra 21a) praises a sage Joshua ben Gamla with the institution of formal Jewish education in the 1st century AD. Ben Gamla instituted schools in every town and made education compulsory from the age of 6 or 7. Prior to this, parents in Judea taught their children informally. Arguably then, today’s Jews have been formally and compulsorily indoctrinated for far longer than other peoples.
The Aztecs (14th to –16th centuries AD) had one of the first compulsory educational systems. Until the age of 14, the education of children was in the hands of their parents, but supervised by the authoritiesof their calpolli. All boys and girls were then required to attend school at age 15 .
The Black Death and the Modern Era
The Black Death which commenced in Europe in the mid 14th century is estimated to have killed 30% to 60% of Europe's population. No area was spared.  This created a series of religious, social and economic upheavals that had profound effects on the course of European history. It took 150 years for Europe's population to recover. The plague returned at various times, resulting in a larger number of deaths, until it left Europe in the 19th century. Figures for the death toll vary widely by area and from source to source but it killed an estimated 75–200 million people in the 14th century. According to medieval historian Philip Daileader in 2007:
The plague repeatedly returned to haunt Europe and the Mediterranean throughout the 14th to 17th centuries, and although bubonic plague still occurs in isolated cases today, the Great Plague of London in 1665–1666 is generally recognised as one of the last major outbreaks. 
In the Thirty Years' War (1618-1648), an estimated eight million Germans were killed by bubonic plague and typhus.  The war was fought mostly in Germany and caused extensive destruction of entire regions, denuded by the foraging armies (bellum se ipsum alet). Episodes of famine and disease significantly decreased the populace of the German states and the Low Countries and Italy, while bankrupting most of the combatant powers.
Europe's last major epidemic occurred in 1720 in Marseilles.
What has this to do with education?
Well, the drastic reductions in population combined with the enclosure of the Commons and the expulsion of peasants from the land in the 15th to 17th centuries combined with the British and Scottish Agricultural Revolutions in the 18th century created industrial changes which, together with the lure of emigration to the New World, caused the collapse of the post feudal population control system. That necessitating the development of a new socio-political system to ensure the retention of power by the ruling monarchical and aristocratic elites.
Up until the 19th century education was largely the preserve of the aristocracy and the clergy, and the leading merchants and military families. Schooling was not available to well over 90% of the European population – the peasants who worked the land and lived in perpetual servitude, owned by or in debt to local aristocrats, lords and landlords and subject to crushing taxes, rents, interest payments and the like.
Typical of the attitude of aristocratic rulers at the time was the Anglo-Irish ruling class’ attitude to the Irish potato famine of 1847-49 which killed over two million people by starvation and caused another million to flee (mostly to the US). The history books don’t evidence the actual death numbers nor do they usually tell us that during the entire duration of that "famine" Ireland was a food-exporting nation. Wheat, rye, barley, corn, and other staple foods were exported from Ireland to England in more than adequate quantities to feed the starving millions of Ireland during each and every year of the famine, but because nearly all the farmland of Ireland was owned by wealthy English, the landless Irish peasants were forced by poverty and guns to harvest those crops and load them onto ships bound for England, while millions of their countrymen (most, actually, women and children, who weren't as useful for field labour) died of starvation. Wheat was for the English: potatoes for the Irish; this was a fact known to every Irishman, and any who cared to avoid being shot or hung didn't question it. So when the potato blight wiped out the potato crop for several years, it was the Irish who died, while Londoners continued to bake their breads from fine Irish wheat and wear clothes made from Irish linen and wool.
The Irish situation was not unique. Famine, starvation and malnutrition was the peasant’s lot all over Europe in the 1840s, and generally. Small weather changes or a local war, caused famine among peasant populations. Apart from the plague tens of millions of European peasants died of starvation and malnutrition in the four centuries to 1800. The social unrest this caused led to the emergence of the idea of compulsory state public schooling as a means of socially engineering compliance by the masses. 
The first modem public schools were founded in the German state of Gotha in 1524; three years later, Thuringa set up public schools. In 1559, compulsory attendance was inaugurated in Wurttemberg. Luther himself drew up a plan for Saxony. The purpose of all those school systems was to impose Lutheranism as the local aristocracy was breaking away from the Holy Roman Empire and its Catholicism. Similarly, in the mid-16th century, John Calvin set up mandatory schools in Geneva, which were used to stamp out dissent. Under Calvin's influence, Holland followed suit in the beginning of the 17th century. It is important to understand that the purpose of these schools was to indoctrinate the citizens in the official religious outlook, for, as Luther put it, "no secular prince can permit his subjects to be divided by the preaching of opposite doctrines.... Heretics are not to be disputed with, but to be condemned unheard. " So it’s no surprise that it was in Calvinist New England that compulsory schooling first arrived in the US.
However, the first state education system (the Gymnasium high-school system) was set up by King Frederick William I of Prussia in 1717. His son, Frederick the Great, following in his father's footsteps, said: "The prince is to the nation he governs what the head is to the man; it is his duty to see, think and act for the whole community." But the compulsory state system wasn’t fully implemented until later.
The Austrian famine of 1771-1772, combined with the increasingly brazen exploitation of children by mercantilists, led to a tense political situation for the ruling families of Austria and Prussia. Traditionally, peasants were kept in line by fear or threats of starvation. But the Austrian and Prussian governments' inability or unwillingness to move in the direction of any sort of social equality combined with the desperation of famine and the theft of children to work in manufacturing had pushed the populace to a dangerous level of anger. In effect the old way of keeping the peasants in line wasn’t working; something new was necessary. And so the Prussian state revisited the ideas of Ernst Wilhelm von Schlabrendorff.
In 1755, Schlabrendorff took over the Prussian region of Silesia (now part Germany, part Poland). In January, 1756, he toured the region he was now responsible for, and discovered poverty and discontent which he considered dangerous. Among other things, in 1756, Schlabrendorff suggested to Prussian King Frederick II that a system of state-run, compulsory schools be established. He said that extraordinary benefits could come from it.
Schlabrendorff reckoned that: * By molding young minds, it would be possible to create the belief that work was a necessary and moral imperative. Work was Good, even if the fruits of it ended up with a corporate or royal dynasty, even if it meant five or six days of toil a week just to provide basic essentials for the family. * Schools could inculcate proper political opinions in children: there would never again be a generation who would grow up to revolt against their government. * Children would learn not to question authority or authority figures, be they governmental or corporate. (The practice of forcing pupils to raise their hand to ask a question, essentially asking permission to ask, was pioneered by Johann Hecker in 1740 in Prussia.) * Children would learn to accept their lot in life and to limit their aspirations: the needs of the factories for workers and the army for soldiers would be met with compliant recruits. * Children's primary loyalty and fear would be shifted from their mother and father to the king and the state. This would be ensured by the children learning very early that if they didn't attend school, special truant police would come after them, a force their parents were powerless to stop.
Initially Schlabrendorff ideas were not implemented. But in 1763, at the end of the Seven Year War, King Frederick II was willing to try them. Many of the early schools were educational facilities in the morning, factories for making wool or silk in the afternoon. They were known as Spinnschulen. Prussian Minister von Schlabrendorff issued an edict in late 1763 that every Silesian town must provide such compulsory instruction to all children ages seven to fifteen (with the exception, of course, of the children of the landholding royal families). In 1765, Queen Maria Theresa of Austria passed an identical law in Austria.
The use of compulsory, state-controlled education as a replacement for the gallows, the rack, the whip, and the prison cell as a way to keep the peasantry in line was suddenly popular across Germany and Austria. A leading German, Chrisian Frchtegott Gellert, believed this would not only lead to a more docile populace, but a more moral one as well. A student of his, philosopher Karl Heinrich Seibt, wrote in 1771: "If laws are to be faithfully observed, the subject of the state must obey them freely and willingly. The enlightened state which educates each subject in the duties of his profession, a state whose subjects fulfill their duties willingly and out of love this is a powerful, invincible, and blessed state."
The Prussian and Austrian authorities were proud of the fact that their public compulsory education was designed to create a compliant citizenry. In 1774 when the Gymnasium high-school system was reformed in Prussia, its main architect, Mathes Inaz von Hess, suggested that class, and not ability, should determine the quality of a child's education. This would assure stability, he said: 'If bright children of low social class were only to learn to be compliant labourers, it would be "no loss to society."' The Prussian Education Edict of 1776 demanded that children of high social class be admitted to higher education even if they were of "only mediocre talent and little proficiency," keeping the "children from the lower orders" in the state-run compulsory system. Children of wealth could attend private schools: the overt goal of the compulsory public educational system, wrote Johann Ignaz von Felbiger, was to make lower-class students "content with the station into which they are born." 
As the Industrial Revolution gathered pace after 1800 due to increased manufacturing stimulated by imported gold from South America, and money made in the rum, tobaco and slave-trading between the Americas and Africa, adults in Europe began to resent the competition of children for jobs. By 1805, fewer than half of all employed skilled workers in Berlin were members of guilds. Concern began to arise about "child labor." As a consequence, and no doubt stimulated by the defeat of the professional Prussian army by Napolean’s army of volunteer farmers in 1807, King Fredrick William III replaced The Spinnschulen with full-day educational programs.
To strengthen the state’s hold on society King Frederick William III decided, among other things, to revamp Prussia’s school system to improve its ability to indoctrinate children to become obedient soldiers and workers. He instituted certification of teachers and abolished semi-religious private schools. High-school graduation examinations were necessary to enter the learned professions and the civil service. Children aged 7 to 14 had to attend school. Parents could be fined or have their children taken away if the children did not attend. Private schools could exist only as long as they kept to the standards of the government's schools. An official language was imposed through the schools, to the prejudice of ethnic groups living in Prussia." 
This Prussian compulsory schooling model became praised and echoed by German and Austrian philosophers, leaders, and educators (such as Fichte, Raab, Hitler, and others) for the next 150 years.
In 1910 Ernst Troeltsch pointed out the obvious: "The school organization parallels that of the army, the public school corresponds to the popular army." The German philosopher Johann Fichte was a key contributor to the formation of the German school system. It was Fichte who said that the schools "must fashion the person, and fashion him in such a way that he simply cannot will otherwise than what you wish him to will." 
But what has this got to do with US education?
Well, around 1850, the legislature of the State of Massachusetts was grappling with a problem that had an explosive potential similar to that faced by King Frederick and Queen Maria Theresa a century earlier. Millions of Irish Catholics had poured into Boston largely as a result of the Irish Potato Famine, and their numbers were threatening the Protestant power structure in the state legislature. At that time, there was no compulsory or state-controlled education in the US and yet (unsurprisingly) USans were regarded even by the Germans as the most well-educated and well-read people in the world.
To break the back of the growing Catholic power base in the Boston area, in 1852 the Massachusetts legislature, encouraged by Horace Mann, enacted the first compulsory US education law. Over the next six years many parents were jailed and thousands of children marched off to school by the state militia, as entire "revolting" towns were militarized when they refused to take their children out of their locally-run schools or home-schools and place them in the state-run, state-controlled institutions. The last town to fall, Barnstable, Massachusetts, capitulated in 1858 after a massive invasion by police and the state militia: compulsory public state-run education had begun in America.
By 1900, nearly every state had government schools and compulsory attendance. At first, only elementary education was provided by the state. Later, the government system was extended to high school. These days, the many advocates of public schooling want the state to provide day care beginning at an early age and year-round schooling. The trend is unmistakable.
Sheldon Richman says of US education in 1900:
‘At the time schooling was plentiful, innovative, and well within the reach of the common people in the US. Jack High and Jerome Ellig say that 80 percent of New Yorkers leaving wills could sign their names. Other data show that from 1650 to 1795, male literacy climbed from 60 to 90 percent and female literacy went from 30 to 45 percent. Between 1800 and 1840, literacy in the North rose from 75 percent to between 91 and 97 percent. And in the South during the same span, the rate grew from 50-60 percent to 81 percent. Senator Edward M. Kennedy's office issued a paper stating that the literacy rate in Massachusetts has never been as high as it was before compulsory schooling was instituted. Before 1850, when Massachusetts became the first state in the United States to force children to go to school, literacy was at 98 percent. When Kennedy's office released the paper, it was 91 percent.
According to Carl F. Kaestle, "Literacy was quite general in the middle
reaches of society and above. The best generalization possible is that
New York, like other American towns of the Revolutionary period, had a
high literacy rate relative to other places in the world, and that literacy
did not depend primarily upon the schools." Another indication of the high
rate of literacy is book sales. Thomas
Paine's pamphlet Common
Sense sold 120,000 copies in a colonial population of 3 million
(counting the 20 percent who were slaves)the equivalent of 10 million copies
today. In 1818, when the United States had a population of under 20 million,
Noah Webster's Spelling Book sold over 5 million copies. Walter
Scott's novels sold that many copies between 1813 and 1823, which would
be the equivalent of selling 60 million copies in the United States today.
of the MohicansJames
Fenimore Cooper sold millions of copies. John
Taylor Gatto notes that Scott's and Cooper's books were not easy reading.
European visitors to early nineteenth-century America - such as Alexis
de Tocqueville and Pierre
du Pont de Nemours marveled at how well educated the people were.' 
So what happened to change this happy state of educational affairs in the US?
In truth the highly educated US population in 1900 was a tribute to the vitality and drive of ordinary USans rather than their leaders. For instance it is not generally understood that the libertarian streak in the US was not endorsed by many key figures in the Revolutionary period and later community leaders. For instance Benjamin Rush, a physician and signer of the Declaration of Independence. was an early proponent of state control of education." In 1786, Rush devised a plan for public schools in Pennsylvania. He wrote:
‘It is necessary to impose upon them [children] the doctrines and discipline of a particular church. Man is naturally an ungovernable animal, and observations on particular societies and countries will teach us that when we add the restraints of ecclesiastical to those of domestic and civil government, we produce in him the highest degrees of order and virtue.’
Sheldon Richman says of Rush:
‘Rush saw the schools as the means to "convert men into republican machines. This must be done if we expect them to perform their parts properly in the great machine of the government of the state." He also saw the schools as essential for making up for the failings of the deteriorating family. As he put it, "Society owes a great deal of its order and happiness to the deficiencies of parental government being supplied by those habits of obedience and subordination which are contracted at schools." He was clear about the role of schools. "The authority of our masters [should] be as absolute as possible," he said. "By this mode of education, we prepare our youth for the subordination of laws and thereby qualify them for becoming good citizens of the republic."He took that position because he believed that useful citizens were manufactured from children who "have never known or felt their own wills till they were one and twenty years of age."
… What should the state schools teach the student? "He must be taught to amass wealth, but it must be only to increase his power of contribution to the wants and needs of the state." Furthermore, this signer of the Declaration said, "Let our pupil be taught that he does not belong to himself, but that he is public property. Let him be taught to love his family, but let him be taught at the same time that he must forsake and even forget them when the welfare of his country requires it."
Similarly, Richman quotes Archibald D. Murphey, founder of the North Carolina public schools, writing in 1816:
‘In these schools the precepts of morality and religion should be inculcated, and habits of subordination and obedience be formed .... Their parents know not how to instruct them.... The state, in the warmth of her affection and solicitude for their welfare, must take charge of those children and place them in school where their minds can be enlightened and their hearts trained to virtue.’
Horace Mann, a former Calvinist, and many other US educators and sociologists in the 19th century were enamoured of similar anti-personal, anti-social and anti-freedom ideas.
For instance in Dumbing Us Down: The Hidden Curriculum of Compulsory Schooling John Taylor Gatto tells us:
‘A small number of very passionate American ideological leaders visited Prussia in the first half of the 19th century; fell in love with the order, obedience, and efficiency of its education system; and campaigned relentlessly thereafter to bring the Prussian vision to these shores. Prussia's ultimate goal was to unify Germany; the Americans' was to mold hordes of immigrant Catholics to a national consensus based on a northern European cultural model. To do that, children would have to be removed from their parents and from inappropriate cultural influences.’ 
Sheldon Richman says:
Gatto emphasizes how the Prussian model set the standard for educational systems right up to the present. "The whole system was built on the premise that isolation from first-hand information and fragmentation of the abstract information presented by teachers would result in obedient and subordinate graduates, properly respectful of arbitrary orders," he writes. He says the American educationists imported three major ideas from Prussia. The first was that the purpose of state schooling was not intellectual training but the conditioning of children "to obedience, subordination, and collective life." Thus, memorization outranked thinking. Second, whole ideas were broken into fragmented "subjects" and school days were divided into fixed periods "so that self-motivation to learn would be muted by ceaseless interruptions." Third, the state was posited as the true parent of children. All of this was done in the name of a scientific approach to education, although, Gatto says, "no body of theory exists to accurately define the way children learn, or what learning is of most worth."
Gatto's reference to the so-called ‘scientific approach to education’ refers to Wundtian psychology and the absurd behaviourist theories that emerged from it and insinuated themselves into US education in the 20th century.
Richman quotes Horace Mann and other movers and shakers in US education in the 19th century at some length but the above references give you the picture. Clearly the dumbing down of USans did not emerge from left field. It was always in the minds of the planners well before 1900.
The indispensable key to using the educational system to dumb down the US populace was compulsory school attendance for as long as possible and from the earliest age possible, If children are free to attend nonstate schools or to avoid formal schooling altogether, the state's control efforts could be thwarted. The state's seemingly benevolent goal of universal education is actually an insidious effort to capture and propagandise all children in its social engineering matrix. Accordingly the indispensable key to using the educational system to create a compliant and ignorant citizenry is compulsory attendance.
The aim of compulsory state education in Prussia and in the US from its inception at the macro or social level was the creation of a homogeneous, national, Protestant culture: the Protestantization of all citizens. In the US this was also aimed at the Americanization of the disparate ethnic and religious elements (especially Catholics) and disparate groups that populated the US. At the micro, or individual, level the aim was the creation of conformist citizens, people who trust and defer to government in any areas it chooses to claim. In this context Americanization presupposes the remaking of the individuals who comprise population.
The actual means for achieving this national dumbing down of the US population from its place at the pinnacle of global educational achievement at the turn of the 20th century to the current situation in which USans must rank among the least educated people in any economically advanced country at the beginning of the 21st century is the story of the rise of Wundtian psychology and Rockefeller finance in the intervening century.
Peasants and Lords
Following the collapse of the Roman Empire, new kingdoms arose in Europe in the centuries just prior to 1000 AD. With very few exceptions, all land was owned by the kings and their families, and the people living on the land were considered property of the landowner, just as much as the trees and the wild animals. In exchange for a place to live and space to grow a garden, these landless peasants worked the land for their lords, normally five or six days a week. Stealing food from the fields, or hunting wild animals in the lord's forest, were offences which were often punished by death; so common was this practice that it gave rise to legends and stories such as those of Robin Hood. The land and its fruits were considered more valuable and better defended by the armies and police of the lords and kings than were the always-replaceable peasants.
The history of the years from 1400 to 1800 is littered with episodic plagues and famines among the poor, such as the Black Death and the German (Bohemian) famines of the early 1700s. That people were forced to gather food for the royalty while being unable to eat any of it themselves under threat of torture or death led to a number of uprisings, such as the 1680 revolt in Bohemia, the uprisings in Prussia in 1719 and 1723, the 1762 and 1765 revolts in Eisenburg, the 1766 peasant uprising in Austrian Selesia, and the most massive revolt in German Bohemia in 1775, which took two years and the lives of 40,000 soldiers to quell.
In the lands we now call Germany, Austria and the Czech Republic , the leaders at the time of that last and most bloody uprising were King Leopold II of Bohemia, and Queen Maria Theresa of Austria. Both were shaken by the ferocity of the peasant uprisings, coming, as they did, around the same time as the American War of Independence and the French Revolution which shook Britain and most of the rest of Europe. In 1776, Austrian Queen Maria Theresa wrote, "not in Bohemia alone are the peasants to be feared, but also in Moravia, Styria, Austria. At our very doors, here at home, they create the greatest impudences. The consequences for themselves and for many innocent people [a code phrase for the royalty] are to be feared."
Historically, the peasants had been controlled by fear of force. Murder, torture, kidnappings, rape of family members, imprisonment, public flogging and hanging: all were commonplace occurrences in the daily life of 90 to 95 percent of all humans then alive in Europe.
Children were expected to work alongside their parents in the fields, and in the mid-18th century, with the beginnings of the Industrial Revolution Austria and Germany began exporting fabric made from the spinning of wool or flax and children were forced into this work. In a 1775 letter to Christoph Friedrich von Derschau, then in charge of Brandenberg, King Leopold II wrote: "While children of eight or nine years can do little by way of strenuous work, they at least can spin" Our wool merchants presently complain so much about the lack of spinners: yet if these children were put to work, this shortage would be eased"
This perspective was shared by royalty all across Europe. Maria Theresa of Austria issued a formal decree in 1761 which said that, "Our manufacturers are in great need of spinners and they would gladly employ children [of the poor] for this purpose."
When children didn't "volunteer" for the work or their parents were unwilling to force them into the spinneries, the families were often declared "unfit" and the children declared "orphans." [This is an eerie parallel with today’s government Social Services ability to take children from their parents] In fact, other than war orphans and in the largest cities, true orphans were a rarity in rural Europe: extended families were almost always available to take in a child if both parents were to die, as families at that time were not mobile because they could only move if they were sold by one landowner to another.
But orphanages began to appear all over the German (Prussian, Bohemian) and Austrian countryside. And most of the children in the orphanages worked as spinners of wool for the wealthy families who established the orphanages. In 1724, for example, a wing was added to the Vienna Workhouse (Zucht- und Arbeitshaus) where wool and silk were spun: that wing the first orphanage in Austria's history. In 1730, the Oriental Company opened an orphanage/spinning factory; in 1742 the Viennese aristocrat Michael Kienmayr opened an orphanage on the Rennweg in Vienna to house workers for his silk factory next door. Orphanages began to erupt all over Europe, nearly always connected to silk or wool factories, including a huge one on the Waldstein estate in Oberleutensdorf (1754), and the famous Waldstein stocking factory in Weisswasser (1767).
Not all the children in the orphanages only spun wool or silk, as Horst Kruger pointed out in his book Zur Geschichte der Manufacturen und der Manufakturarbeiter in Preussen. In 1747, the government of Prussia issued an edict that the children could not go out of their orphanages at night, because so many of the orphanages were doubling as bordellos, and their managers as procurers. (Maria Theresa of Austria issued a similar edict in 1765.) While both edicts were largely ignored (nearly a hundred years later, England would establish the age of consent at 12), they did acknowledge a growing problem which had brought about an earlier "strike" in 1705 by the children of the Halle, Prussia orphanage/wool factory. Nonetheless, there was a healthy trade in "orphans" throughout the century: in 1740 the Berlin Wool Factory and Orphanage had begun contracting out their children to other manufacturers, and the Du Vigneau orphanage for girls in Berlin originally started in 1743 by the widow Madame Du Vigneau, who died shortly thereafter ñ was acquired in 1763 by the lace-manufacturing firm Ephriagm and Sons. Even the priest who heard the confessions of Queen Maria Theresa's husband Franz Stephen got into the act, generously taking over a boy's orphanage in Rennweg, Austria, in 1759.