Which mathematicians are very famous from the past that not many people know?

Well, this question has certainly shot itself in the foot.

If not many people know of a person, then by definition, it certainly seems that he can't be [very]8 famous.

As shining stars in the history of math who are, nonetheless, far from being household names, I would propose Pythagoras, Archimedes, Lorentz, Fermat, and Murray (Queen Isabella's court mathematician).