René Descartes

The man who married algebra and geometry on the coordinate plane

Descartes was the French philosopher and mathematician famous for 'I think, therefore I am.' By representing a point on the plane as a pair of coordinates (x, y), he opened the door to analytic geometry — moving freely from shapes to equations and back. The unknowns x and y and the exponent notation xⁿ we still use took their modern form in his hands.