After gaining a degree at Oxford, I was sent by Sir Walter Raleigh in 1585 to accompany Sir Richard Grenville on his "expedition to the New World."
I wrote my major mathematical work Artis Analyticae Praxis in 1610, but it unfortunately was not published until 1631 (ten years after my death).
This algebra text focused on the formation of equations from given roots, the relation of these roots to the equation's coefficients, and my eponymic "Law" for determining the number of roots of an equation.
Also, I helped improve algebraic notation, introducing the symbols < and > for ordering relationships.
French and English mathematicians often have battled over Descartes' apparent plagiarism of my mathematical ideas.
My other interest was astronomy, where I was one of the first to use a telescope, discovered sunspots (independenly of Galileo), and proposed the refraction law (prior to both Snell and Descartes).
Answer:
Thomas Harriot (1560  1621)
