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/
The History of the Decimal Point table mentions the following people, and here are some links in order to find out more about them.
Stevin:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Stevin.html
Viète:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Viete.html
Kepler:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Kepler.html
Napier:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Napier.html
Oughtred:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Oughtred.html
Ozanam:
http://www-history.mcs.st-and.ac.uk/~history/Mathematicians/Ozanam.html