Many scientists and historians consider Isaac Newton (1643–1727) one of the most influential people of all time. It was Newton who discovered the laws of motion and universal gravitation, made huge breakthroughs in light and optics, built the first reflecting telescope, and developed calculus. His discoveries published in Philosophiæ Naturalis Principia Mathematica, or The Principia, and in Optiks are unparalleled and formed the basis for mechanics and optics. Both these books were written in Latin and published only when friends demanded that he publish, many years after Newton had completed his work.