Prussia studied the city-state of Sparta. Why?
First, a little about Sparta, a city-state which was basically a war-mongering nation in what is now Greece. Everything centered around the military.
Spartans were essentially sorted into castes; Spartiates (receiving all rights), Mothakes (non-Spartan men treated as Spartans), Perioikoi (freed men), and Helots (state-owned slaves and enslaved non-Spartan residents).
Helots had violent uprisings often, so the Spartiates and especially Perioikoi were trained in warfare to squash Helot dissenters. A secret police existed to kill Helots to keep them under control. The only way for a Spartan man to achieve high rank in society was to become a secret police, those able to kill for the state were the only ones "worthy" of distinction and rights.
The Helots' lives were quite under the control of the government. The government could call upon them at any time to serve at war. Additionally, they did not own land but rather rented it and had to obtain government permission to move.
Spartan government practiced infanticide, a eugenic principle, where every newborn was inspected for its worthiness and exterminated if deemed inferior or unnecessary.
The secret police were rather intertwined with the agoge, Sparta's educational system, which took boys from the home at age 7 to train them for battle, making them state-owned until death.
The agoge, in addition to its focus on militarism, promoted conformity and the importance of the state over an individual's desires, wants, interests. Loyalty was to be to the school, not the boy's family.
Prussian education used some of Sparta's agoge philosophies in that Prussian education was to train a military state which placed honor of State and King above self and family.
However Prussia educated all its citizens and had a special school for the elite and the education modeled after Sparta was for the approximately 94% of Prussians (I have yet to find the social stratification percentages for Sparta), the non elite inferiors that needed to be "managed"... this is reminiscent of the management of Sparta's Helots. Both promoted compulsory education and total state obedience.
How did Prussian Education become, well, American? And how are Spartan and Prussian ideals still evident in our educational systems today? Well, that is for another post.