History 5-6

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.
https://mathshistory.st-andrews.ac.uk/HistTopics/History_overview

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:
https://mathshistory.st-andrews.ac.uk/Biographies/Stevin

Viète:
https://mathshistory.st-andrews.ac.uk/Biographies/Viete

Kepler:
https://mathshistory.st-andrews.ac.uk/Biographies/Kepler

Napier:
https://mathshistory.st-andrews.ac.uk/Biographies/Napier

Oughtred:
https://mathshistory.st-andrews.ac.uk/Biographies/Oughtred

Ozanam:
https://mathshistory.st-andrews.ac.uk/Biographies/Ozanam