Sir Isaac Newton Sir Isaac Newton is one of the most influential scientist of all time. He was an English mathematician, astronomer, physicist, and a key factor in the scientific revolution. Newton developed the principles of today's physics. In 1687, he published Philosophiae Naturalis Principia Mathematica, which has been called the most influential book in science. He is most well known for his discovery of gravity and his study of optics/prisms. Sir Isaac Newton was born December 25, 1642, according to the Julian calendar which was used at that time. He was born in the in the Lincolnshire county in England. When he was very young his mother got married and moved away so Isaac stayed with his grandmother. When Newton was 12 she returned