At the beginning of the year 1860, the ruler Alexandru Ioan Cuza builds the 2nd secondary school in romanian language from Bucharest, naming it after the founder of schooling in the romanian language on the Wallachian land, Gheorghe Lazăr.
On May 20th 1890, the king Carol I signs the decree that confirms the setting up of the highschool, which will move in a new building near Cișmigiu, that will mix the Brâncoveanu style with the english neoclassical one.
After the year 1900, Lazăr Highschool becomes one of the most important in the country, and will be at the forefront of the education reform with its numerous accomplishments: establishing a museum and a library, constructing a modern gymnasium, creating a group of scouts, a choir and an orchestra, etc.
In 1931 a new wing is built, with laboratories, an amphitheatre and a buffet at the semi-basement. The pupils have numerous accomplishments in this period, especially the orchestra and the math circle, where the well known mathematician Dan Barbilian will be formed.