A Cadet corps (Russian: Kadetskiy korpus, Кадетский корпус), historically an admissions-based all-boys military cadets school, prepared boys to become commissioned officers in Imperial Russia. Boys entered a cadet corps between the ages of 8 and 15. Empress Anna Ivanovna founded the first cadet corps in Saint Petersburg, Russian Empire, in 1731. The term of education was seven years. All instructors had a military rank; they taught a full program of military preparation. In 1766 Catherine the Great's educational reforms broadened the curriculum to include the sciences, philosophy, ethics, history, and international law.
A graduate from the corps became a junker and had prime candidacy for a military career.
During the October Revolution and the 1917-1923 Russian Civil War, cadets and junkers largely supported the anti-bolshevik White movement. (Distinguish the military cadets of this era from the members of the Constitutional Democratic Party, known from its initials (KD) as Kadets. The Constitutional Democratic Party also opposed Bolshevism.) A small portion of cadets succeeded in evacuating with the White Army towards the end of Russian Civil War to western countries. Subsequently, the Soviet Government executed or imprisoned all surviving cadets to Siberian GULAG slave-labor camps. Fifteen years later, according to Alexander Solzhenitsyn, none remained alive and free inside the USSR.
Many cadets who escaped alive formed cadet corps in other countries, most notably at Bela Crkva in the Kingdom of Yugoslavia, where they received the patronage of King Alexander I of Yugoslavia (reigned 1921-1934) - himself a former pupil in the Saint Petersburg Page Corps.