In 1872 a fund for Tallinna Peetri Reaalkool (Petri-Realschule zu Reval) was founded and in 1881 the school opened as a German-speaking high school for boys. A Mathematics teacher Peter Osse became the first headmaster.
In the summer 1881 the main subjects - Mathematics, Russian, Drawing, Geography, French, German and Science - were appointed by the School Board. In the first year, students were only accepted to the second and third grade. Next year, a fourth grade was opened where also English and Physics were taught. From January 1886 teaching in Russian intensified because of the growing russification.
In 1883 a new school house, which is still used today, was built by architects Max Hoeppener and Carl Jacoby. Until then the school had rented rooms in the Old Town on Lai street.
The first class graduated in 1885 with 6 students. One of them was Mihkel Vitsut, the first Estonian to have graduated from Tallinn Secondary School of Science.