20th century: wars lead to new orientations

After 1870, the Army reinforces its position as the Polytechnicians’ first employer, but scientific studies are not abandoned.


Organization of the first annual ball of École Polytechnique, the Bal de l’X, by the Société Amicale de Secours.


École Polytechnique celebrates its 100th anniversary. General André (X1857) welcomes the President of the French Republic Sadi Carnot (X1857).

1914-1918 : World War

The times of war hold sway over École Polytechnique until 1919. Its facilities are used as a military hospital. No national entrance exam is organized in 1915. Over 800 Polytechnicians die in the First World War, including 260 students from the classes of X1911 to X1918.


Students of foreign nationalities are allowed to take the entrance exam.


Inauguration of the École Polytechnique monument to the dead, the Winged Victory of Segoffin, built with the aid of a subscription.


Louis Leprince-Ringuet is designated as a professor of Physics. The physicist establishes École Polytechnique’s first laboratory in 1937: the Leprince-Ringuet Laboratory (LLR). Creation of the first physics laboratories (1937-1940).

1940-1944 : The French State (Vichy)

After the armistice and occupation of northern France, École Polytechnique is relocated to Lyon and once again loses its military status. Its buildings in Paris are allocated to the Red Cross.


After the occupation of the free zone, the School returns to Paris.


250 students die in military campaigns in Africa, France and Germany, and as Maquis resistance fighters. 60 die in deportation, 33 are named “Companions of the Liberation”.

1944-1946 : Provisional Government of the French Republic

In September 1944, École Polytechnique returns under the administration of the Ministry of War

1946-1958 : Fourth Republic

The decree of January 28, 1957, greatly modifies the composition of the Development Council of the school. Louis Armand is named President of the Council.