In 1794, when Sophie was 18, the Ecole Polytechnique was founded in Paris. It was an academy to train mathematicians and scientists for the country, but women were not allowed to enroll. Nevertheless, Sophie was able to obtain the lecture notes for several of the courses and study from them. This gave her the opportunity to learn from many of the prominent mathematicians of those days. Sophie was particularly interested in the teachings of Joseph Louis Lagrange. Under the pseudonym of M. LeBlanc (a former student of Lagrange's), she submitted a paper on analysis to Lagrange at the end of the term. He was quite impressed with the work and wanted to meet the student who had written it. He was amazed that the author of the work was actually a female; he recognized her abilities and became her mentor. With a male to introduce her, Sophie could enter the circle of scientists and mathematicians that she never before could. Up until this point not only had her gender been a hindrance to her, but her social status had been too, because she was not an aristocratic woman but one of the middle class. Lagrange certainly made his colleagues aware that Germain was a girl with mathematical talent and several of them wrote to her; for instance, Monge. But not everyone treated her with the respect she deserved. One case was Jérôme Lalande. She started to talk to him about Laplace's Exposition du système du monde. Lalande told her that she should not be reading such works, rather she should be reading the second edition of his book Astronomie des dames. This "astronomy for ladies" does not contain a single mathematical equation and Germain felt insulted by his suggestion. Lalande sent her a letter of apology but she never forgave him. 