Rene Descartes

is responsible for having applied algebra to geometry—an application which has furnished the key to the greatest discoveries in all branches of mathematics.

As long as algebra and geometry travelled separate paths their advance was slow and their applications limited. But when these two sciences joined company, they drew from each other fresh vitality and thenceforward marched on at a rapid pace towards perfection. It is to Descartes that we owe the application of algebra to geometry,—an application which has furnished the key to the greatest discoveries in all branches of mathematics.

Joseph Louis LagrangeThinkers

Joseph Louis Lagrange