Born in Pisa, Italy, I intended to become a priest, but at my father's urging studied medicine at the University of Pisa...and soon abandoned that to focus on mathematics.
My first academic position was as an instructor of perspective, but soon became the Chair of the Mathematics group at the University of Pisa.
While my mathematical applications in physics were innovative, I taught and used a fairly standard mathematics.
My eponymic paradox is my only piece of original mathematics, and it showed a 1-1 equivalence between the perfect squares and the whole numbers, even though one is a proper part of the other.
My theoretical and experimental work in physics on the motions of bodies (e.g. dropping balls from a tower) provided a stepping stone to Newton's classical mechanics.
When I defended Copernicus' heliocentrism before Catholic church panels and the Pope, I was found "vehemently suspect of heresy" and placed in prison and later house arrest for the remainder of my life.
Galileo Galilei (1564 - 1642)