Hamilton, Sir William Rowan
Mathematician, the inventor of quaternions, born in Dublin, Ireland. At the age of nine he knew 13 languages, and at 15 he had read Newton's Principia, and begun original investigations. In 1827, while still an undergraduate, he was appointed professor of astronomy at Dublin and Irish Astronomer Royal; in 1835 he was knighted. His first published work was on optics, and he then developed a new approach to dynamics which became of importance in the 20th-c development of quantum mechanics. He introduced quaternions as a new algebraic approach to three-dimensional geometry, and they proved to be the seed of much modern algebra.