John Wallis (1616-1703), Mathematician
Sitter in 10 portraits
John Wallis was a mathematician who played a part in the development of modern calculus and is credited with introducing the symbol for infinity. Having discovered a facility for code breaking, Wallis became a cryptographer on behalf of the Parliamentary party during the Civil War. He was a founding member of the Royal Society, and contributed more than sixty papers and several reviews of mathematical books to the society's Philosophical Transactions. In 1649, Wallis was appointed Savilian Professor of Geometry at Oxford. He held his professorship for over half a century, and became known as one of the leading mathematicians of his time.