This is one of the best all around sites that I have found. It is titled “The MacTutor History of
Mathematics Archive.”
http://www-history.mcs.st-and.ac.uk/~history/
This is an award-winning site that links to all sorts of mathematics information.
http://archives.math.utk.edu/
Here are the biographical sites related to this section:
Euclid: http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Euclid.html
Proclus: http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Proclus.html
Legendre:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Legendre.html
Bolyai:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Bolyai.html
Playfair:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Playfair.html
Lambert:http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Lambert.html
Gauss:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Gauss.html
Lobachevski:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Lobachevsky.html
Riemann:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Riemann.html