On 1 April 1776 Marie-Sophie Germain was born into a bourgeois family of several generations of merchants in Paris. Her father Ambroise-François Germain was an active deputy of the Third Estate at the Constituent Assembly of 1789. Sophie Germain remained dependent on her family throughout her life, as she never married or acquired any social position.
It was at the age of 13 that Sophie developed a passion for mathematics after reading a chapter in the library on the life and death of Archimedes. Although her parents did not encourage her to do so, she discovered her vocation and read everything she could get her hands on, creating her own translations of certain classical works. It is said that she even got up at night while her parents slept to study by candlelight.
At the age of 19, she managed to obtain courses at the male-only Ecole Polytechnique by borrowing the identity of a former student Antoine Auguste Le Blanc. The self-taught man sent his remarks to Professor Lagrange, who eventually discovered the imposture. Impressed by the girl's brilliant answers, he became her friend and mentor.
Number theory was the first area in which Sophie Germain made an important contribution. She read Gauss's Disquisitiones Arithmeticae, published in 1801, and exchanged 12 letters with him between 1804 and 1809, still under the pseudonym of Mr Le Blanc.
Following the visit of the German physicist Chladni to Paris in 1809, Sophie Germain radically changed her mathematical orientation. For more than a decade, she was interested in the theory of surfaces (mainly their curvature) and the problem of vibration of elastic surfaces. She presented several memoirs to the Académie des Sciences and violently opposed Poisson on these subjects. Although she had some good ideas, she suffered from her somewhat disordered mathematical culture.
The mathematician was the first woman to be able to attend lectures at the Académie des Sciences and she continued to work on mathematics and philosophy until the end of her life.
She died on 27 June 1831, a victim of breast cancer.
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