However, Germain’s most famous correspondence began in 1804 with the German mathematician Carl Friedrich Gauss. She was intrigued with his work in number theory and sent him some of the results of her work. Again, she used her pseudonym to disguise her true identity; she feared being ignored because of being a woman. It was not until 1807 that Gauss found out who M. LeBlanc truly was. He was thrilled to find that his "pen pal" was a very gifted woman. Gauss was amazed for seeing that all the excellent that he could find in the interchange of letters and discussions came from a female, considered the weak gender. He was not bothered but pleased. 