Isaac Newton is known for inventing calculus among other things. His main focus was on gravitational pull and motion laws. These were the basis of his invention of calculus. He came about calculus as he made efforts to describe the rate at which an object was falling. As he did so, he realizes that the falling object increased its speed every second. The lack of mathematical explanations to address this was what prompted the invention of calculus. This led to the development of the infinitesimal calculus theory in the 17th century.