Isaac Newton is probably one of the smartest people of all time. Aside from discovering the foundations of physics, he was also the first person to describe the force of gravity. He designed the first practical reflecting telescope and explained how colours work based on the phenomenon of white light splitting into a rainbow after passing through a prism. He has been credited with inventing ridge-edged coins (to fight counterfeiting) and the cat-flap door (seriously), and was an influential religious philosopher. But my favourite story about Newton is the following.

Around 1666, Newton locked himself in his room for a while and, basically, invented calculus.^{[1]}Calculus is a set of concepts and techniques, completely new to the usual addition-subtraction-multiplication kind of math, which allowed people to finally use numbers to describe changes — like the change of position (velocity) or the change of velocity (acceleration). But despite the enormous importance of this invention, for some reason, Newton didn’t tell anyone about it for years afterwards. He mentioned some of the basics in an annotation to a footnote somewhere, and actually used calculus in his major physics works, but never published the original paper on calculus itself. A few years later, a man named Gottfried Wilhelm Leibniz also invented calculus, completely independently of Newton’s work. Newton got fairly upset about this, accusing Leibniz of plagiarizing from, well, the papers that he had failed to show anybody.

- If any math historians are currently reading this, please forgive the impreciseness in this paragraph. ↩