Sir Isaac Newton's came from a family of farmers.  As a child he did not do well in school, mostly showing on interest to the subjects.  His mother wanted him to become a farmer, but his uncle encouraged him to go to college, and he was sent to Trinity College where he planned to study law. His most important  contributions to mathematics occurred in the middle part of his life, 1669 to 1687. The college closed in 1665 because of the plague, and so Newton went to Lincolnshire where he made many advances in astronomy, mathematics, optics and physics.  In mathematics he made the foundation of integral and differential calculus, calling the inverse procedure of differentiating "the method of fluxions."  Then he used this process to find areas, tangents, and the maxima and minima of functions.  Previously these were thought of as unrelated, but he showed through calculus that
they actually were.  In optics he discovered that white light was made of the spectrum, merged together.  In physics he made the theory of universal gravitation.  He also made the laws of motion (F=ma and others).  In 1693 he had a nervous breakdown and started working for the government,  ending his career in mathematics and physics.

Author: Charles DeBoer

References:
http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/Newton.html.

http://128.163.113.57/lifeandthought.html