Belief in the need for universal compulsory education actually has a long historical pedigree, going back many centuries.
Pierre Dubois (c. 1255 – after. 1321) a medieval French canon lawyer, advocated egalitarian state-funded education for boys and girls equally; whereby the most talented children of every social class, gender and kingdom in Europe would be trained at internationally-run schools. He also taught basic universal education for all children, writing:
"It is especially desirable that every catholic should know written figures, the situation and places of the elements, their magnitude and shapes the thickness of the celestial orbs, their magnitude; the velocity, motion, and influences of sun, moon, and other stars; and how small the earth is compared to them, and how great with respect to man"
See:
The Codification of Public International Law
By Ramaa Prasad Dhokalia
https://books.google.co.uk/books?id=DHa7AAAAIAAJ&pg=PA6&lpg=PA6&dq=pierre+dubois+education+international+schools+medieval&source=bl&ots=XbkNpkmOLv&sig=IH3G0rdf29cklAF2NINR0aMcyEg&hl=en&sa=X&ved=0ahUKEwigxdf_54_cAhWKKcAKHZ-PBw8Q6AEIVzAE#v=onepage&q=pierre dubois education international schools medieval&f=false
Dubois was the first propose an international court of arbitration. He urged that a state waging war be boycotted...a recommendation that received notice only six centuries later, in the Covenant of the League of Nations.
He advocated that the money that would be saved through the abolition of wars should be used for the establishment of international schools, and was thus one of the earliest proponents of international education.
Here's a link to his
1309 Scheme of Education:
Pierre Dubois' Scheme of Education, 1309
In each province, according to the resources of the localities available for this purpose and the size of the population, instead of the priories of the Templars or Hospitalers there located, there should be established what would be more opportune for this purpose two or more schools for boys and about the same number for girls, who should be chosen to be instructed there at the age of four or five years...
These students and their teachers shall live on the goods of the said priories and the funds provided for the Holy Land, or as the trustees of the foundation, selected by the archbishop with the advice of skilled suffragans, may see fit to arrange.
All these children shall be instructed first in the Latin language to the extent that they know it sufficiently, or at first little by little; and after that they shall be instructed more fully, some of them in Greek, others in Arabic, and so with other literary idioms, especially of the catholics in the far east, so that in the end the Roman church and likewise catholic princes may through them, instructed in speaking and writing in all languages, communicate with all men, drawing them to the catholic faith and the unity of its single head.
Now when the youth are instructed in grammar, in which the younger are occupied, if some are instructed in logic, so much the better. Of whom let some be rapidly instructed in the articles of faith and sacraments the Old and New Testaments; so that instructed, as soon as they are prepared, they may be sent to the said land to take charge of souls and may be promoted to the priesthood, and provision be made for the churches and people. Let others be trained in medicine, others in surgery both human and veterinary, by whom the whole army and populace of both sexes may be helped.
Girls should be instructed in medicine and surgery with other subjects prerequisite to these. These girls, thus trained and knowing how to write...
It could hardly help but be the case that they, nobler and richer than other matrons and everywhere having knowledge of medicine and surgery and experimental science, would attract matrons who required their counsels, who admired their prudence and proficiency, and who loved them on these accounts could attract these strongly to communicating with them, delighting and agreeing in the same articles of faith and sacraments.
Also any future pope, at such time as such persons could be instructed in the idioms of oriental catholics, would keep near his court such elegantly lettered persons through whom he could write to the prelates and other magnates of those regions. Greek scholars could easily be procured for this purpose. Moreover, when in the more remote schools many were well founded in Latin and Greek, those who seemed to get on better than the others and were more teachable should be selected to study, hear lectures, and afterwards teach, some in civil and canon law, others in astronomy and in other mathematical and natural sciences, others in theology, others in medicine...
By provision of schools of this sort and transmission of instructors of both sexes to oriental parts we westerners would get trade in precious commodities abounding in those regions, lacking to us and very dear here, and we would import them cheaply once the world were made catholic....
Then let them begin to hear natural science...
Moreover, in mathematical sciences on account of their many utilities, especially touched upon in the little book Super utilitatibus made by brother Roger Bacon of the Order of Minorites, it will be advisable to instruct some disciples of this foundation, as they shall appear to show intelligence, skill, and speed therein, but rather dwelling on those matters which may be of service in taking and keeping the Holy Land.
It is especially desirable that every catholic should know written figures, the situation and places of the elements, their magnitude and shapes the thickness of the celestial orbs, their magnitude; the velocity, motion, and influences of sun, moon, and other stars; and how small the earth is compared to them, and how great with respect to man; so that admiration of these may swell the praise of their Creator, and that, repelling the lust for things worldly, man may not grow proud because of all these inferior things, which are as nothing in the universe that contains them all, and should be regarded as nothing....
It will be advisable that all the girls of the foundation like the males be instructed in Latin grammar, afterwards in logic, and in one other language, later in the rudiments of natural science, finally in surgery and medicine.
Later on, the 17th century Protestant theologian
Comenius:
John Amos Comenius - Wikipedia
John Amos Comenius (Czech: Jan Amos Komenský; German: Johann Amos Comenius; Latinized: Ioannes Amos Comenius; 28 March 1592 – 15 November 1670)[1] was a Czech philosopher, pedagogue and theologian from the Margraviate of Moravia[2][3] and is considered the father of modern education.[4][5] He served as the last bishop of Unity of the Brethren and became a religious refugeea nd one of the earliest champions of universal education. As an educator and theologian, he led schools and advised governments across Protestant Europe through the middle of the seventeenth century.
[He] supported lifelong learning and development of logical thinking by moving from dull memorization, presented and supported the idea of equal opportunity for impoverished children, opened doors to education for women, and made instruction universal and practical.
Given its attestation that far back, I doubt it could have been posited as unique in the 19th century.